Sidebar updates

## What does this MR do?
Updates `nav/_admin.html.haml` and `nav/_explore.html.haml` to match new compact sidebar design

## Screenshots (if relevant)
![Screen_Shot_2016-06-07_at_2.19.18_PM](/uploads/5699987001de901a67d503b097d1b19d/Screen_Shot_2016-06-07_at_2.19.18_PM.png)

See merge request !4517

Update Knapsack report only on master

## What does this MR do?

Makes to generate Knapsack report only on master. This speed-ups tests, because the last stage can be run significant time after previous stages.


See merge request !4540

Optimize issuable APIs interaction with notes

See merge request !4471

Remove notification settings in batches

## What does this MR do?

This improves the performance of the migration `db/migrate/20160603180330_remove_duplicated_notification_settings.rb` by removing duplicate rows in batches instead of using a single big `DELETE FROM` query.

## Why was this MR needed?

The original migration would locally take 45 minutes to complete, possibly up to hours on GitLab.com and similar setups.

## What are the relevant issue numbers?

#18289

See merge request !4529

Removable labels from filtered issuables label bar

When filtering by labels, a remove button appears next to each label. This then removes that label & refreshes the issuable filter form

![Screen_Shot_2016-05-17_at_12.07.47](/uploads/b21e86247aa1bbfd347bef1eb21f1562/Screen_Shot_2016-05-17_at_12.07.47.png)

Closes #15474

See merge request !4178

Backported from EE shared form for web hooks

## What does this MR do?

EE uses a shared form for web hooks - so this brings that across to CE.

See merge request !4457

This was not a clear cut n+1 query, given that if you're directly subscribed to all issues
that the API is returning you never really need to check for the notes. However, if you're
subscribed to _all_ of them, then for each issuable you need to go once to `notes`, and
once to `users` (for the authors). By preemtively loading notes and authors, at worst you have
1 extra query, and at best you saved 2n extra queries. We also took advantage of this preloading
of notes when counting user notes.

`notes_with_associations` are used for `participant` declarations, but `Participable`
only really cares about the target entity project, and not the participants
projects.

`notes_with_associations` are also used in `Commit::has_been_reverted?` which
employs the reference extractor of the commit, so no references to the notes
projects are made there (`Mentionable::all_references` cares only about the
`author` and other `attr_mentionable`). A paralel situation occurs on
`Issue::referenced_merge_requests`.

This improves performance of the duplicate notification settings
migration by removing duplicates in batches instead of using one big
"DELETE FROM" query.

The previous query would locally run over 45 minutes without even
finishing. This new setup finished in a matter of seconds.

Fixes #18289

Add fog-azure to supported backup list

!4396 left out Azure by accident.


See merge request !4444

Dismantling Grack::Auth part 1: Git HTTP clients

Part of https://gitlab.com/gitlab-org/gitlab-ce/issues/14501

This does not completely get rid of Grack::Auth yet because Git LFS
support is 'behind' it and I would like to not make this MR bigger
than needed.

- changed tests to make HTTP requests instead of calling Rack apps
- added missing test cases for Git HTTP authentication
- moved Git HTTP requests into a 'normal' Rails controller

See merge request !3361

Fix endless redirections when accessing user OAuth applications when they are disabled

## What does this MR do?

This MR fixes a bug where the browser would be redirect endlessly when attempting to access the user's OAuth applications when an admin has disabled this system-wide setting.

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

I assume disabling the nav button is better than showing a page that says, "OAuth applications are disabled by the admin."

## Why was this MR needed?

Lots of users were confused when they hit endless redirect errors.

## What are the relevant issue numbers?

#14770 

See merge request !4525

Fix markdown_spec to not use `before(:all)` in order to properly cleanup database after testing



See merge request !4515

Also hides the "Applications" nav button if OAuth applications are disabled by the admin.

Closes #14770

Add a test for User#ci_authorized_runners

## What does this MR do?

Add a test for User#ci_authorized_runners

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

Should we add `Project#add_user` so that it's similar to `Group#add_user`?

## Why was this MR needed?

I am going to make some changes to this method for !4093, but I couldn't find a corresponding test so I want to add it in case I would break anything.

## What are the relevant issue numbers?

This is a test for current behaviour, before implementing #3407

See merge request !4404

Check if GitHub rate limite API was reached before update Webhooks

## What does this MR do?

Checks if the job needs to sleep, and wait for the rate limit to be reseted before update each Webhook.

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

No.

## Why was this MR needed?

The import process can fail if the API rate limit was reached during the import process.

## What are the relevant issue numbers?

https://gitlab.com/gitlab-org/gitlab-ce/issues/17498

## Screenshots (if relevant)

Not relevant.

See merge request !4509

Enable Knapsack only in CI environment

Fixes running tests locally. Enables Knapsack only in CI environment.

cc @grzesiek 

See merge request !4528

Added tests

When filtering by labels, a remove button appears next to each label. This then removes that label & refreshes the issuable filter form

Closes #15474

Conflicts:
	lib/gitlab/workhorse.rb

Add flexbox to project header

## What does this MR do?
Adds flexbox to project header to keep components vertically centered regardless of description presence/length

## What are the relevant issue numbers?
Closes  #18080 

## Screenshots (if relevant)
![Screen_Shot_2016-06-01_at_12.02.42_PM](/uploads/edd769110b52ec34046f4079619e45eb/Screen_Shot_2016-06-01_at_12.02.42_PM.png)     
![Screen_Shot_2016-06-01_at_12.02.35_PM](/uploads/c5c2828ba5688a2588d3721a2d21d5fe/Screen_Shot_2016-06-01_at_12.02.35_PM.png)

See merge request !4417

Change color of canceled ci text to gray

## What does this MR do?
Change text color of Canceled builds from `$gl-danger` to `$gl-gray`

## What are the relevant issue numbers?
Closes #18074 

## Screenshots (if relevant)
<img src="/uploads/f2ac59c5081c31cfb34bdc0470e31384/Screen_Shot_2016-06-01_at_10.38.17_AM.png" width="600px">

See merge request !4412

Bump recaptcha gem to 3.0.0 to remove deprecated stoken support

Google deprecated the use of stoken in its reCAPTCHA, so this gem is
necessary to make things work again.

Closes #18210 

See merge request !4484

Optimise email CSS for speed with Premailer

Speed up emails-on-push by removing all descendant selectors from the
CSS they use, which can make the CSS inlining much more efficient in
certain cases.

See: https://gitlab.com/gitlab-org/gitlab-ee/issues/490

See merge request !4511

Bump nokogiri to 1.6.8

Number of important security and bug fixes. See:
https://github.com/sparklemotion/nokogiri/blob/master/CHANGELOG.md#168--2016-06-06

See merge request !4500

Closes #18210

Load knapsack in Rakefile only when is bundled

Fixes `production` builds: https://dev.gitlab.org/gitlab/omnibus-gitlab/builds/85407

cc @marin 

See merge request !4514

Notifications dropdown on project page now has descriptions

## What does this MR do?

Adds descriptions to the notification settings dropdown on project pages. Also changed the order of them to make more sense.

## What are the relevant issue numbers?

Part of #12758

## Screenshots (if relevant)

![Screen_Shot_2016-05-31_at_09.35.24](/uploads/b30d82701a13ec15f672139e1225acf5/Screen_Shot_2016-05-31_at_09.35.24.png)

See merge request !4374