Use forked github-markup gem to enable python3 support with omnibus

## What does this MR do?
Changes the version of `github-markup` gem we are using, to be the forked one with the changes to enable python3 support.
The change is backward compatible with users using Python 2, and will only be running with Python 3 in Omnibus (with the help of a custom patch we apply there).

## Are there points in the code the reviewer needs to double check?
Make sure backward compatibility isn't broken for source installs.

## For the release manager

You need to make sure you pickup into stable this merge request as well (for omnibus): https://gitlab.com/gitlab-org/omnibus-gitlab/merge_requests/1015 as it's part of the fix, otherwise package will fail to build.

## Why was this MR needed?
We had some regressions with .rst rendering that were fixed, but still some issues with encoding persisted (this MR will fix that). See: https://gitlab.com/gitlab-org/gitlab-ce/issues/21696

## Screenshots (if relevant)

## Does this MR meet the acceptance criteria?

- [ ] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [ ] Added for this feature/bug
  - [ ] All builds are passing
- [ ] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [ ] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [ ] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

* gitlab-org/gitlab-ce#21696
* gitlab-org/gitlab-ce#22748
* gitlab-com/support-forum#1097

See merge request !6659

GrapeDSL for variables



See merge request !6838

Merge branch '23234-deleting-a-milestone-removes-source-branch-deletion-options-of-associated-merge-requests' into 'master'

Maintain "force_remove_source_branch" options on Merge Request unless specified

## What does this MR do?

Fixes a problem where Merge Requests were losing the state associated with the flag to remove the source branch upon merge

* Closes #23234 
* Closes #23191
* Closes #19351

See merge request !6817

Keep a copy of gems needed by our releases as CI artifacts

This is meant as insurance in case a gem GitLab needs is ever removed
from rubygems.org. After we merge this, all future GitLab tags will
have a CI artifact archive containing all the gems (for all platforms)
specified in Gemfile.lock for that revision.

Only runs on tags (so we don't constantly create 50MB gem cache bundles).

See merge request !6617

Add job to trigger a docs.gitlab.com build

## What does this MR do?

Add a job to build the docs site every time master tests pass.

## What are the relevant issue numbers?

https://gitlab.com/gitlab-com/doc-gitlab-com/issues/56

See merge request !6850

Implement second iteration of cycle analytics - Change in data measurement

Part of https://gitlab.com/gitlab-org/gitlab-ce/issues/22458

Measure everything that happened in the given time range, not only what's been pushed to production. With the exception of the staging and production stages.

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [x] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- Tests
  - [x] Added for this feature/bug
  - [x] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !6798

Fix secret names in HA docs

See https://gitlab.com/gitlab-org/gitlab-ee/issues/1110#note_16854559. I don't think this needs a CHANGELOG item really.

See merge request !6845

Fixed default branch dropdown not converting to select2

## What does this MR do?

The LFS dropdown doesn't have the `data` attribute & it isn't needed because it doesn't hide/show any elements. This filters out the `<select>` without that attribute.

## What are the relevant issue numbers?

Closes #23200

See merge request !6810

Fix overflow to show grouped builds arrow

## What does this MR do?
Removes overflow style so that the arrow shows up again

## Screenshots (if relevant)
Before:   
![Screen_Shot_2016-10-11_at_9.11.55_AM](/uploads/92d2a0c34d2af050e58468c8d61f4cd3/Screen_Shot_2016-10-11_at_9.11.55_AM.png)
After:   
![Screen_Shot_2016-10-11_at_9.11.41_AM](/uploads/2c4c422a21fb6450d00ae638aef29d89/Screen_Shot_2016-10-11_at_9.11.41_AM.png)
Scrolling:   
![Screen_Shot_2016-10-11_at_9.40.36_AM](/uploads/e5b1e3125d881c5882cf199026110d48/Screen_Shot_2016-10-11_at_9.40.36_AM.png)

See merge request !6808

Trigger Merge When Pipeline Succeeds on pipeline event

## What does this MR do?

This MR is meant to improve merge when build succeeds triggers, which has an impact on performance.

- [x] Move Merge When Build Succeeds trigger from commit status to pipeline event
- [x] Drop support for triggering event for branches that include commit status submitted without branch (no longer relevant)
- [x] Perform Merge When Pipeline Succeeds asynchronously to improve performance and avoid race conditions
- [x] Add missing feature test that verifies if MWBS feature actually works and merges merge requests
- [x] Update the documentation to reflect change in the behavior

Moved to separate merge request:

- [ ] Rename Merge When Build Succeeds to Merge When Pipeline Succeeds
- [ ] Update documentation to reflect name change for this feature

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- Tests
  - [x] Added for this feature/bug
  - [x] All builds are passing

See merge request !6675

Ensure that whitespace doesn't cause adding members to fail

I recently had to debug an issue where adding users wasn't working. It turned out that I was hitting "space" to confirm a `select2` dialog, and the server would throw out the whole email address because it was invalid. It looked as though GitLab was entirely ignoring my add-member request.

Here's a fun gif:
![out](/uploads/5c306addb764067bca54add3b7a53c6c/out.gif)

Ideally, there should also be validation client-side, so that the server doesn't need to silently fail, and the user will know what's going wrong. I'll look into creating an issue for that.

Additionally, GitLab already seems to trim email addresses, sometimes? If you add _two_ address, with spaces, then the `value` of the `user_ids` DOM element will have the first `n-1` addresses without spaces. Weird.

**TL;DR: Now spaces are always trimmed from new-member email addresses.**

See merge request !3443

Fix "Copy to clipboard" action button has a mismatching white background.

## What does this MR do?
Adds a class to all the clipboard icons which removes the extra padding.
It also fixes some odd overlay when over the clipboard icon in commits list.

## Are there points in the code the reviewer needs to double check?
No.

## Why was this MR needed?
To fix the extra padding and background color that was visible when it should not be

## Screenshots (if relevant)
![commits_list](/uploads/f988e2e2e2aea41fe3f7fe41c8a857ef/commits_list.png)
![file](/uploads/ce97909fc4e602af47fea46b8fffb7ad/file.png)

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [ ] Added for this feature/bug
  - [x] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?
Closes #22635

See merge request !6785

Improve appearance_spec and deploy_key_spec

In appearance_spec.rb we can use build instead create record in db. In deploy_key_spec.rb we can remove unused code.

See merge request !6819

Union examples in event spec for speed up

## What does this MR do?

Increase tests speed for event model.

## Why was this MR needed?

This change saves about 15-18 seconds.

See merge request !6821

Update to gitlab-shell 3.6.6

## What does this MR do?

This updates gitlab-shell to version 3.6.6

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- Tests
  - [ ] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

See merge request !6830

Document Capybara errors from es6 in es5 file.

## What does this MR do?

Documents an error that I've banged my head against twice now. 

## Are there points in the code the reviewer needs to double check?

## Why was this MR needed?

The greater good. 

## Screenshots (if relevant)

## Does this MR meet the acceptance criteria?

- [ ] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [x] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [ ] Added for this feature/bug
  - [ ] All builds are passing
- [ ] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [ ] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [ ] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

See merge request !6836

Fix step number and token param in URL example. Fix gitlab-rails command code formatting.



See merge request !6791

Improve merge request versions compare logic

## What does this MR do?

Changes the way how we compare between for merge request versions 

## Are there points in the code the reviewer needs to double check?

no 

## Why was this MR needed?

So when I squash+rebase my commit I can get more accurate diff on what changed between versions

## Screenshots (if relevant)

in discussion (below)

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [ ] ~~[Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)~~
- [ ] ~~API support added~~
- Tests
  - [x] Added for this feature/bug
  - [x] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

https://gitlab.com/gitlab-org/gitlab-ce/issues/22368, https://gitlab.com/gitlab-org/gitlab-ce/issues/22721

See merge request !6589

* master:
  Update health_check gem to `~> 2.2.0`
  API: Version information
  Revert "Merge branch 'tests-use-tmpfs' into 'master'"
  Added documentation chapter for Git attributes
  Use activerecord_sane_schema_dumper
  Add a separate stage for bundle check
  Add a bundle check step to ensure dependencies are correct
  Create a new /templates API namespace
  Add disabled delete button to protected branches
  Make spec deterministic
  refactors tests because of gitlab-test repository changes
  Addresses Robert's feedback
  Speed up specs for GET /projects/:id/events
  API: New /users/:id/events endpoint
  writes tests to verify the issue is solved and fixes breaking issues.
  removes inconsistency regarding tagging immediately as merged once you create a branch using new branch button and adds changelog entry

API: Version information

## What does this MR do?

Adds a new endpoint to retrieve the version information.

## Why was this MR needed?

Clients can now use this information to enable/disable certain API features depending on the version.  

## What are the relevant issue numbers?

Closes #22608, https://gitlab.com/gitlab-org/gitlab-ce/issues/23148

See merge request !6822

Update health_check gem to `~> 2.2.0`

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/22278

See merge request !6835

Add a bundle check step to ensure dependencies are correct

This should help prevent merge issues in the future, which caused !6814 to be needed.

See merge request !6815

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/22278

Resolve "Move `/licenses` api endpoint to `/templates/licenses`"

## What does this MR do?

It moves the `/licenses`, `/gitignores` and `/gitlab_ci_ymls` API endpoints under the `/templates` namespace

## Why was this MR needed?

In EE we now have somewhat ambiguous API endpoints. `/license` refers to the EE license while `/licenses` (plural) refers to license templates. @DouweM mentioned that we're adding .gitignore templates in #14106 so it may make sense to add a /templates namespace. Then, move the /license templates endpoint to be underneath, along with .gitignore endpoints. 

Closes #17541

See merge request !5717

This reverts merge request !6730

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Added documentation chapter for Git attributes

See https://gitlab.com/gitlab-org/gitlab_git/issues/28 for more information.

See merge request !6826

Use activerecord_sane_schema_dumper

## What does this MR do?

> `ActiveRecord::SaneSchemaDumper` modifies the behavior of Rails’ `ActiveRecord::SchemaDumper` so that the generated `db/schema.rb` file doesn’t contain any useless/harmful whitespace column alignment.

## Why was this MR needed?

To reduce potential conflicts in `db/schema.rb` (see https://gitlab.com/gitlab-org/gitlab-ee/issues/715).

See merge request !6827