Cache autocomplete results

## What does this MR do?

Caches the results of the autocomplete AJAX call to stop new GFM inputs on the page from requesting new data. The cache is then cleared on each new page so that it doesn't stay around per project.

See merge request !5043

Improve the request / withdraw access button

## What does this MR do?

It implements the design proposed in #18310.

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

No.

## Why was this MR needed?

To close #18310.

## What are the relevant issue numbers?

Closes #18310.

## Screenshots

### Group access request

#### Request button

| Medium | Large |
| ----------- | ------- |
| ![request_access_button](/uploads/a1de370dcbb8ac9a63d2df5c68591db7/request_access_button.png) | ![request_access_button-large](/uploads/0a1c70380268e620a6ca4d3e1661d58c/request_access_button-large.png) |

#### Withdraw request button

| Medium | Large |
| ----------- | ------- |
| ![withdraw_access_request_button](/uploads/c9df39d04b61566ec143d5e9cc43ada2/withdraw_access_request_button.png) | ![withdraw_access_request_button-large](/uploads/10fdaa94d72956e06bdb995e65b51472/withdraw_access_request_button-large.png) |

### Project access request

#### Request button

| Medium | Large |
| ----------- | ------- |
| ![request_access_button](/uploads/8e71395041a5cea996a35df2083bb723/request_access_button.png) | ![project-request_access_button-large](/uploads/adb2dec0eccec8e5171dc0e26e6b03a6/project-request_access_button-large.png) |

#### Withdraw request button

| Medium | Large |
| ----------- | ------- |
| ![withdraw_access_request_button](/uploads/12be06f0a2bf9426a5e043f52c4d1dab/withdraw_access_request_button.png) | ![project-withdraw_access_request_button-large](/uploads/93fda7767ee5f02186c4c954ea346254/project-withdraw_access_request_button-large.png) |

## Does this MR meet the acceptance criteria?

- [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] 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 !4860

Specific metrics for code on Banzai::Filter::SyntaxHighlightFilter

See merge request !5038

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

Admin should be able to turn shared runners into specific ones:

## What does this MR do?

Make sure admins could turn shared runners into specific runners.

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

Is this the desired behaviour?

## Why was this MR needed?

Closes #19039
Closes #19272

![Screen_Shot_2016-06-30_at_9.30.05_PM](/uploads/97eb3b4923fd4e498b1f8ca70b1345c8/Screen_Shot_2016-06-30_at_9.30.05_PM.png)

See merge request !4961

Avoid instantiation of a Git::Tree

See merge request !4997

* upstream/master: (120 commits)
  Update CHANGELOG for 8.9.4, 8.8.7, and 8.7.9.
  Remove additional entries from CHANGELOG
  Catch permission denied errors and ignore the disk
  Remove coveralls lines
  Make GH one-off auth the default again for importing GH projects
  Import from Github using Personal Access Tokens.
  Remove hardcoded gitlab-shell version in test env now that the required tag is published
  Updated breakpoint for sidebar pinning
  Expire branch/tag git data when needed.
  Remove unnecessary parens
  Enable Style/UnneededCapitalW Rubocop cop
  Expiry date on pinned nav cookie
  Fix broken spec in git_push_service_spec by stubbing an external issue tracker
  Handle external issues in IssueReferenceFilter
  Move Changelog entry for build retry fix to 8.9.4
  Add Changelog entry for build sidebar retry link fix
  Improve method that tells if build is retryable
  Do not show build retry link when build is active
  Remove coveralls as its unused
  Move changelot item "Add sub nav to file page view" to 8.9.4
  ...

Catch permission denied errors and ignore the disk



See merge request !5017

[ci skip]

Remove duplicated entries from CHANGELOG

[ci skip]

See merge request !5028

Build path sends JSON file path

## What does this MR do?

Fixes an issue with browser caching JSON response on build page.

Steps to see:

- Open build (https://gitlab.com/gitlab-org/gitlab-ce/builds/2030226)
- Close tab
- Re-open tab

You should now see some JSON 😞 

This MR appends `.json` to the end of the build URL so that the browser can't cache it as the same URL.


See merge request !4935

Cleanup forgotten lines

The `coveralls` gem was unused and thus removed in 7a2f25a8. I've forgotten some lines in that MR

See merge request !5025

Do not show build retry link when build is active

Closes #19244

See merge request !4967

Remove hardcoded gitlab-shell version in test env now that the required tag is published

See merge request !5023

Handle external issues in IssueReferenceFilter

Rendering issue references such as `#1` was broken for projects using an external issues tracker.

See gitlab-org/gitlab-ce#19036

See merge request !4988

Allow importing from Github using Personal Access Tokens

_Originally opened at !4005 by @ericidema._

------

## What does this MR do?

* Made changes to `Gitlab::GithubImport::Client` so that it can be used with Github Personal Access Tokens without the need for OAuth.
* Added UI to collect Personal Access Token from user.
* Detect if the user has logged in with GitHub and use OAuth to skip the Personal Access Token form.

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

Twin Omnibus MR: https://gitlab.com/gitlab-org/omnibus-gitlab/merge_requests/774

## What are the relevant issue numbers?

Closes #13970.

## Screenshots

### GitHub import is configured

![github_import_configured](/uploads/151e4f0edf3f87bfa03c2d97dda8b3d8/github_import_configured.png)

-----

### GitHub import is not configured

![github_import_not_configured](/uploads/cb129f7e2ffe66cceb28ccd9af480284/github_import_not_configured.png)

-----

## Does this MR meet the acceptance criteria?

- [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
  - [ ] All builds are passing
- [ ] 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 !4938

Fix wrong line in changelog

## What does this MR do?

Fix a wrong line in the changelog



See merge request !5008

Fix restore warning message

## What does this MR do?

Fix the restore Rake task so it properly outputs the database warning. This is a pretty important warning and it was not even being output. After this fix, the output looks like the screenshot below.

![Screen_Shot_2016-06-28_at_3.53.46_PM](/uploads/d250189d39fcacd0c8ec0aacf9cd930d/Screen_Shot_2016-06-28_at_3.53.46_PM.png)

See merge request !4980

Advertise the PAT as an alternative unless GH import is not configured.
Signed-off-by: Rémy Coutable <remy@rymai.me>

This stands as an alternative to using OAuth to access a user's Github
repositories.  This is setup in such a way that it can be used without OAuth
configuration.

From a UI perspective, the how to import modal has been replaced by a full
page, which includes a form for posting a personal access token back to the
Import::GithubController.

If the user has logged in via GitHub, skip the Personal Access Token and go
directly to Github for an access token via OAuth.

Updated breakpoint for sidebar pinning

## What does this MR do?

Updates the breakpoint for sidebar pinning to 1024px.

Think we will have the same issue as before when picking into stable with `$window` not being defined.

See merge request !5019

Project dashboard appears to be loading tags on every request

See merge request !4996

Make Rack::Request use our trusted proxies when filtering IP addresses

## What does this MR do?

This allows us to control the trusted proxies while deployed in a private network.

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

If we want to limit what is impacted, we can do this specifically for the rack_attack request object.

## Why was this MR needed?

Normally Rack::Request will trust all private IPs as trusted proxies, which can cause problems if your users are connection on you network via private IP ranges.
    
Normally in a rails app this is handled by action_dispatch request, but rack_attack is specifically using the Rack::Request object instead.

## What are the relevant issue numbers?

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/17550

## 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)
- [ ] 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)


\cc @stanhu

See merge request !4958

Remove unnecessary parens and other code style fixes

This MR is based on reviewers` comments to https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/440

See merge request !5015

Enable Style/UnneededCapitalW Rubocop cop

## What does this MR do?

This MR enables Rubocop cop that checks if `%W[]`, which supports interpolation, is needed.

## What are the relevant issue numbers?

#17478 

See merge request !5010

Expiry date on pinned nav cookie

## What does this MR do?

Adds an expiry date far into the future for the pinned nav cookie so that it survives logout & browser closing.

See merge request !5009

When pushing commits to existing branches we don’t
need to flush branch git data (branch names / counts)

When flushes the cache when pushing commits skip to
flush branch and tag git data (names / counts) because
those operations are managed explicitly in each case

Repopulated expired cache as soon as possible

There's little point to cut that down.

Feedback from:
https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/4961#note_12794221

Global Ajax error handler

## What does this MR do?
Introduces a new global Ajax error handler to show a flash warning about the error detail of XHR requests which failed with status code 404 and 500

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

## Why was this MR needed?
A global solution for the problem in the #17880

## What are the relevant issue numbers?
Fixes #17880 

## Screenshots (if relevant)

For requests failed with 404 - 500 

![Screen_Shot_2016-06-21_at_00.07.26](/uploads/04bb3a5a958c3d21aef4fd12bd3d105a/Screen_Shot_2016-06-21_at_00.07.26.png)

For requests failed with 401

![Screen_Shot_2016-06-21_at_00.08.30](/uploads/25cc885ba388f4c6f4c555fa338e1a63/Screen_Shot_2016-06-21_at_00.08.30.png)

See merge request !4797

Loop all disks when displaying system info. Closes #18886



See merge request !4983