Allows empty merge requests for a workflow described in gitlab-org/gitlab-ce#14606

Closes gitlab-org/gitlab-ce#14606

See merge request !6384

Add `robots.txt` to the list of reserved namespaces

See #22759

See merge request !6789

Bump mail_room to v0.8.1 to fix thread cleanup issue

See https://github.com/tpitale/mail_room/blob/master/CHANGELOG.md

Closes #20273

See merge request !6788

Remove NamespacesController

* removes unnecessary NamespacesController. The main purpose of this controller was redirect to group or user page when URL like https://gitlab.com/gitlab-org was used. Now this functionality is handled by constrainers (like this https://gitlab.com/gitlab-org/gitlab-ce/blob/master/config/routes/user.rb#L17-21) and take user to correct controller right from the start.
* serve non existing API routes like `/api/v3/whatever` with Grape instead of Rails. Before this change wrong API url was served by rails with not obvious 404, 405 & 500 errors


See merge request !6733

Formatted all app/assets/javascripts to underscore naming convention

## What does this MR do?

Changes all javascript file names to user underscores as delimiter.

This will be enforced in the docs in a different MR !6782.

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

## Why was this MR needed?

Consistency.

## 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 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 #23118

See merge request !6783

Closes #20273

Changed 'Compare branches, tags or commit ranges' to 'Compare Git revisions'

## What does this MR do?

I remember we had a quick discussion about what to call the expected input of the compare page. Today whilst doing !6766 I found these are called [git revisions](https://git-scm.com/docs/gitrevisions).

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

## Why was this MR needed?

## Screenshots (if relevant)

![Screen_Shot_2016-10-10_at_14.44.13](/uploads/694200b8f56967d8e7caa965bbf7c123/Screen_Shot_2016-10-10_at_14.44.13.png)

Dunno where that gradient came 😆 Screenshot issue not code.

## 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 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 !6774

Changed network input placeholder to 'Git revision'

## What does this MR do?

Changes the commit SHA-1 input placeholder on the network page to `Git revision`. ([as defined here](https://git-scm.com/docs/gitrevisions))

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

## Why was this MR needed?

Placeholder was too complex

## Screenshots (if relevant)

![Screen_Shot_2016-10-10_at_15.06.23](/uploads/e31586b0f7a973b04e55e73223a2a95c/Screen_Shot_2016-10-10_at_15.06.23.png)

## 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 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 #20356

See merge request !6766

Fix inconsistent options dropdown caret on mobile viewports

## What does this MR do?
Change the options dropdown caret from left aligned to right aligned (only visible on mobile viewports)

## Are there points in the code the reviewer needs to double check?
Check if there are any other dropdowns that have left aligned carets

## Why was this MR needed?
Resolve UI inconsistency as some dropdown carets were already right aligned

## Screenshots (if relevant)
Before:
![Simulator_Screen_Shot_Sep_15__2016__11.54.55_AM](/uploads/767d9344db4973af5a5368d5149144cc/Simulator_Screen_Shot_Sep_15__2016__11.54.55_AM.png)

After:
![Simulator_Screen_Shot_Sep_15__2016__11.54.09_AM](/uploads/882614cb9c5f85bf44e118cd7c74fcef/Simulator_Screen_Shot_Sep_15__2016__11.54.09_AM.png)

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) 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 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?
Closes #22086

See merge request !6372

Added copy file path button to diffs

## What does this MR do?

Adds a copy file path button in the header of diff files.

## Screenshots (if relevant)

![Screen_Shot_2016-10-10_at_09.59.48](/uploads/1aedd5033bb3c1893023bb8c8d99a708/Screen_Shot_2016-10-10_at_09.59.48.png)

## What are the relevant issue numbers?

Closes #23108

See merge request !6769

Remove redundant mixins

## What does this MR do?
Removes the following redundant mixins
```
@mixin box-shadow($shadow) {
  box-shadow: $shadow;
}

@mixin border-radius($radius) {
  border-radius: $radius;
}
```

## Are there points in the code the reviewer needs to double check?
Just need to make sure the refactor didn't break anything. Last time I did something like this, we faced an edge case where values `.5` would pass correctly in mixins but not when passed directly to the property.

## Why was this MR needed?

*  Reduces redundant code which leads to happier developers 😄 

## Screenshots (if relevant)
None

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) 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 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?
Closes #22012

See merge request !6287

Add link to test coverage report to README

## What does this MR do?

Since we have GitLab Pages with test coverage report, it makes sense to link coverage badge there, instead of linking to commits page.

See merge request !6772

Rename HTMLEntityFilter to HtmlEntityFilter to fix autoloading

See merge request !6776

Use user from let instead recreate in before

## What does this MR do?
It`s minor fix in tests. We can use factory from let instead recreate user before each test.
 
## Are there points in the code the reviewer needs to double check?
No

## Why was this MR needed?

## Screenshots (if relevant)
No

## 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
  - [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?

See merge request !6762

Improve backup doc readability

From https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/3761

See merge request !6781

[ci skip]

Explain the extra chmod

There is confusion about what passing `0600` to File.open does.

```
$ touch /tmp/foobar
$ ls -l /tmp/foobar
-rw-r--r--  1 jacobvosmaer  wheel  0 Sep 26 14:20 /tmp/foobar
$ ruby -e 'File.open("/tmp/foobar", "w", 0600)'
$ ls -l /tmp/foobar
-rw-r--r--  1 jacobvosmaer  wheel  0 Sep 26 14:20 /tmp/foobar
$ 
$ 
$ rm /tmp/foobar
$ ruby -e 'File.open("/tmp/foobar", "w", 0600)'
$ ls -l /tmp/foobar
-rw-------  1 jacobvosmaer  wheel  0 Sep 26 14:21 /tmp/foobar
```

See merge request !6523

Changes to make Git basics more intuitive

From https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/6420

See merge request !6777

- updated verbiage where appropriate
- changed "git config" commands to include quotes for variables to be more in line with standard practive and to avoid issues with spaces
- updated CHANGELOG as part of commit

Remove Ci::ApplicationController.

See gitlab-org/gitlab-ce!6757.

Signed-off-by: Rémy Coutable <remy@rymai.me>

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

Clarify which token should be used to delete a Runner



See merge request !6775

Changed 'Commit hash' to 'Git revision'

Fix ci pipeline processing with async jobs

## What does this MR do?

This MR fixes CI pipeline processing with asynchronous jobs called from `around_transition` provided by state machine.
For details see  https://github.com/pluginaweek/state_machine/issues/191 and commit f68acbac.

## Why was this MR needed?

Recently merged https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/6650 introduced problem with asynchronous job being deployed when `around_transition` still held transaction, which caused race condition that prevented pipeline status to change in a proper way. 

## What are the relevant issue numbers?

Closes #23111

See merge request !6736

Correct namespace validation to forbid bad names #21077

## What does this MR do?
Updates master namespace regex to forbid any namespace ending in `.git` or `.atom` and corrects and adds relevant tests

## Are there points in the code the reviewer needs to double check?
I think it's all good. I could use help with the creation of tests for usernames with trailing `.atom` or `.git` as the testing framework is a bit over my head.

## Why was this MR needed?
A group that ends in `.atom` will cause the relevent dashboard to crash if the user (ANY user, not just the creator) has visibility of the group until it is deleted through the admin panel (it cannot be renamed, the edit page will crash. It may be fixable through the API, that wasn't checked.)

This allows a malicious user with group creation privileges to bulk add users to a group, rename the group to a bad name, and crash the groups dashboard for all members of the group. The same applies if the group is internal or public and users navigate to the explore tab of the groups dashboard.

The same applies to usernames ending in `.atom`.

In many places of the code, it implies that `.git` in not allowed at the end of namespaces, but many allowed it anyway. This MR forbids it everywhere to prevent potential issues (like the one with `.atom` going forward).

## What are the relevant issue numbers?
Group path validation incomplete, crashes groups dashboard #21077

## 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 [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 !5994

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

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

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

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

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