Getting latest CHANGELOG so I can resolve merge conflict

If notification_email is blank, it's set from email. If an admin
attempted to create a user with an invalid email, an error would be
displayed for both fields. Only validate the notification_email if it's
different from email.

Enable linting for ES6 files

## What does this MR do?

Add `.js.es6` to file extensions checked by ESLint.

## What are the relevant issue numbers?

Follows !5445

See merge request !7156

Document CI pipelines settings

See merge request !5847

[ci skip]

Revert "Revert "Change "Group#web_url" to return "/groups/twitter" rather than "/twitter".""

Looks like I accidently reverted https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/7035 although I did not want to . This MR reverts my revert.

See merge request !7127

Documents that users with two-factor authentication enabled may also need to create a personal access token to use git over HTTPS.

To address a support issue (gitlab-com/support-forum#980) about why passwords don't work in git when two-factor auth is enabled.

gitlab-com/support-forum#980

See merge request !6616

Increase z index on fixed mr tabs

Before:   
<img src="/uploads/e890a4f185af87b66251d744fbe840d5/Screen_Shot_2016-10-26_at_11.58.45_AM.png" width="400px">

After:   
<img src="/uploads/0bbf72888f6a47bd3027ee7dfff542da/Screen_Shot_2016-10-26_at_11.58.28_AM.png" width="400px">
Closes #23866

See merge request !7124

Add todo toggle event

## What does this MR do?
Adds a custom jQuery event `todo:toggle` to detect when a new todo is added so that the respective todo counters (header navigation and sidebar) can update as needed

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

*  I wasn't sure whether each `spec` should be modularized based on the html templates or whether they should be separated based on function. There are some crossovers between the `dashboard_spec` and the `header_spec`.
* The naming conventions for `sidebar` and `right_sidebar` were a little confusing since they were named the opposite in their `specs`. I made a few assumptions and named a few files based on what I thought they should be named. I'd be happy to change it to something else though 😄  

## Why was this MR needed?
This resolves an existing issue where the todo count on the sidebar would not update (until refresh) and refactors the existing methods that are used to update the todo counters (header navigation and sidebar)

## What are the relevant issue numbers?
Closes #20140

## 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
- [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)

See merge request !5724

This reverts commit 9dbd5b3c.

Remove tooltips from build nodes

Before:   
<img src="/uploads/48441dccfe39c5eb1da3dbb9a26e6bd2/Screen_Shot_2016-10-26_at_2.43.46_PM.png" width="400px">
After:   
<img src="/uploads/d72b2ad4603c964283e155e5a2b053fe/Screen_Shot_2016-10-26_at_2.43.31_PM.png" width="400px">
Closes #23868

See merge request !7128

Create new list dropdown stays open after new list

## What does this MR do?

After creating a new list, the dropdown stays open until the user closes the dropdown themselves.

## Screenshots (if relevant)

![keep-open](/uploads/06580dd552647b1a9e5fabc2c978148b/keep-open.gif)

## What are the relevant issue numbers?

Closes #22852

See merge request !6742

Backups fail occasionally with "tar: ./objects: file changed as we read it" error

- [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)
- [x] API support added
- Tests
  - [x] Added for this feature/bug
  - [x] All builds are passing
- [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)

Closes #5613

See merge request !5814

Closes #22852

only.

Fix encoding issues on pipeline commits

## What does this MR do?
#### What does this MR do?
Sets `escape: false` on `truncate` method to fix commit message on pipelines page

#### Screenshots (if relevant)
Before:   
![Screen_Shot_2016-10-12_at_8.53.10_AM](/uploads/5e26e98a272139fe2264c315d579178f/Screen_Shot_2016-10-12_at_8.53.10_AM.png)
After:   
![Screen_Shot_2016-10-12_at_8.52.49_AM](/uploads/58c6c69f2ba735fdcd5a0b6922b56aa7/Screen_Shot_2016-10-12_at_8.52.49_AM.png)

#### What are the relevant issue numbers?
Closes #23258

See merge request !6832

Removed delete branch tooltip

## What does this MR do?

Removed the tooltip on the delete branch button & add `aria-label`

## What are the relevant issue numbers?

Closes #23253

See merge request !6954

Add note about ephemeral statuses in headings

See merge request !7131

[ci skip]

Enable PseudoElement in scss-lint

## What does this MR do?
Enables `PseudoElement` in `.scss-lint.yml`

## Are there points in the code the reviewer needs to double check?
None

## Why was this MR needed?
Improve SCSS maintainability and consistency

## Screenshots (if relevant)
None

## Does this MR meet the acceptance criteria?

- Tests
  - [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)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?
#23485

See merge request !7083

Closes #23253

Resolve "Admin/Overview/Users mobile view"

## What does this MR do?

Fixes mobile layout issues on `/admin/users` page.

* Fixes control element placement when long usernames or email addresses overflow their container
* Fixes condensed dropdown menu (issue caused by acde2e30)

Before:
![Screen_Shot_2016-09-28_at_3.29.11_PM](/uploads/82cd27c367653beb29425065685274dd/Screen_Shot_2016-09-28_at_3.29.11_PM.png)

![Screen_Shot_2016-09-29_at_23.36.40](/uploads/e739638506388be9c5a0709e5f22b298/Screen_Shot_2016-09-29_at_23.36.40.png)

After:
![Screen_Shot_2016-10-24_at_11.55.32_PM](/uploads/ab6e49da85688d9fd2abc49de238a5bf/Screen_Shot_2016-10-24_at_11.55.32_PM.png)

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

Ensure css changes don't have any side effects elsewhere in GitLab.  (I don't think they would...)

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG.md) entry added
- Tests
  - [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)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

Closes #22746

See merge request !7087

Show full status link on MR & commit pipelines

Before:   
![Screen_Shot_2016-10-24_at_2.43.09_PM](/uploads/5543b6e134a5349650b24dcb1b1a9082/Screen_Shot_2016-10-24_at_2.43.09_PM.png)

After:   
![Screen_Shot_2016-10-24_at_2.42.55_PM](/uploads/a561c8708ca2b17d11c0eb9b2cfd0b9b/Screen_Shot_2016-10-24_at_2.42.55_PM.png)

Closes #23607

See merge request !7079

Add ESLint

## What does this MR do?

- create `package.json`
- add ESLint dependencies to `package.json`
- add JavaScript linting to CI
- add Rake task `lint:javascript`as alias for `eslint` (which itself is an alias for `npm run eslint`)

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

Probably not.

## Why was this MR needed?

My hovercraft was full of eels.

## What are the relevant issue numbers?

- https://gitlab.com/gitlab-org/gitlab-ce/issues/13224#note_12537431
- https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/5006#note_13255658


See merge request !5445

Resolve "Lacking padding on syntax highlight blocks in diff comments"

## What does this MR do?

Enforces horizontal padding on highlight block.

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

## Why was this MR needed?

There was no horizontal padding on diff comment highlight blocks.

## Screenshots (if relevant)

![Screen_Shot_2016-10-23_at_01.48.10](/uploads/6d7a426c0856e8787b63b2c02672298a/Screen_Shot_2016-10-23_at_01.48.10.png)

## Does this MR meet the acceptance criteria?

- [ ] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG.md) 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 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 #23661

See merge request !7062

Refactored less readable existance checks

## What does this MR do?
Clean up complex JavaScript expressions generated by conditional assignment and existence checks in CoffeeScript.
These are small changes that effect 1 or 2 lines at a time, but should make sections of code more readable.

## Are there points in the code the reviewer needs to double check?
Changes in [gl_dropdown.js](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/app/assets/javascripts/gl_dropdown.js) don't do much (largely just splitting stuff onto multiple lines). Is this a bit pointless?

## Why was this MR needed?
Auto-generated JS contains complex expressions that will be difficult to work with in future.

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [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?

A child issue of #21887 
Closes #21988

See merge request !6289

Add all endoints to JIRA service API documentation

## What does this MR do?

Add missing API endpoints to the JIRA service.

## What are the relevant issue numbers?

https://gitlab.com/gitlab-org/gitlab-ee/issues/440

See merge request !7122

Closes https://gitlab.com/gitlab-org/gitlab-ee/issues/440