Merge branch '939-repositoryupdatemirrorworker-updatemirrorerror-rugged-invaliderror-cannot-set-empty-url' into 'master'

Fix mirrored projects allowing empty import urls

Because of missing validations in the projects model, you could
create a new project with a nil or empty import_url with mirror=true.
This would cause exceptions when
RepositoryUpdateMirrorWorker::UpdateMirrorError ran and attempted to
update one of these projects. This was made easier by the fact that
you could show the "Mirror repository" checkbox in the UI, check it,
hide it, and still have its value considered.

The missing validations have been added, and minor adjustments have
been made to the UI to improve the previous behaviour. A migration
was also added to update mirror=false in all projects with a nil or
empty import url that exists because of the described bug.

Closes #939

See merge request !700

Because of missing validations in the projects model, you could
create a new project with a nil or empty import_url with mirror=true.
This would cause exceptions when
RepositoryUpdateMirrorWorker::UpdateMirrorError ran and attempted to
update one of these projects. This was made easier by the fact that
you could show the "Mirror repository" checkbox in the UI, check it,
hide it, and still have its value considered.

The missing validations have been added, and minor adjustments have
been made to the UI to improve the previous behaviour. A migration
was also added to update mirror=false in all projects with a nil or
empty import url that exists because of the described bug.

Refactor the license documentaiton

Closes https://gitlab.com/gitlab-org/gitlab-ee/issues/1000

See merge request !730

Request only the LDAP attributes we need

## What does this MR do?

It includes CE changes from https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/6187 to reduce the chance of merge conflicts since lots of stuff moved around. 

Fixes gitlab-org/gitlab-ce#13821. For LDAP users, we really only ever need uid, dn, cn, and mail attributes, and in some cases, even less. For LDAP groups we need ..... This merge request strips the request down to the minimum needed by default, and allows the caller to specify more or less, if needed. 

## Why was this MR needed?

This will improve performance especially in cases where the connection is slow between GitLab and LDAP, or when the LDAP object has lots of attributes we don't care about.

See merge request !712

Fix: Elasticsearch does not find partial matches in project names

Closes https://gitlab.com/gitlab-org/gitlab-ee/issues/960

See merge request !726

Reduce UPDATE queries when moving between import states on projects

See merge request !723

Fix spec in master

Fixes failed builds such as https://gitlab.com/gitlab-org/gitlab-ce/builds/3919501

cherry-picked form https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/6291

See merge request !728

Fixes failed builds such as https://gitlab.com/gitlab-org/gitlab-ce/builds/3919501

Pull import sources from Gitlab::ImportSources

## What does this MR do?
`ApplicationSettings.create_from_defaults` defines an array of import sources, but we should be pulling them from `Gitlab::ImportSources.options` since that's what they're validated against.

## What are the relevant issue numbers?

Closes #21814

See merge request !6293

Improve PipelinesFinder spec so that it does not depend on hard-coded database IDs

Fixes failed builds such as https://gitlab.com/gitlab-org/gitlab-ce/builds/3919501

See merge request !6291

Fixes failed builds such as https://gitlab.com/gitlab-org/gitlab-ce/builds/3919501

Enable pipeline events by default

This should probably be included in !5620 but missed.

See merge request !6278

Restrict ldap return attributes

## What does this MR do?

Fixes the CE part of #13821. We really only ever need uid, dn, cn, and mail attributes, and in some cases, even less. This merge request strips the request down to those four attributes by default, and allows the caller to specify others, if needed. 

## Why was this MR needed?

This will improve performance especially in cases where the connection is slow between GitLab and LDAP, or when the LDAP object has lots of attributes we don't care about.

See merge request !6187

Add update guide for 8.12 CE to EE.

[ci skip]

See merge request !706

Pass the remember_me option into the u2f form and support it while authenticating

## What does this MR do?

Adds remember me support in the u2f authentication, and makes sure the flag gets passed from the login form to the u2f form.

Based on the changes for the same thing done for regular 2fa: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/4369

## Why was this MR needed?

The remember me option wasn't working for u2f devices (yubikey)

## What are the relevant issue numbers?

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/18103

See merge request !5918

Archive CHANGELOG entries prior to 8.0 in CHANGELOGS/archive.md

[ci skip]

See merge request !6162

See gitlab-org/release-tools!29

[ci skip]

[ci skip]

Hides merge request button on branches page

## What does this MR do?

 If user does not have the correct permissions, the merge request button is hidden

## What are the relevant issue numbers?

Closes #21805

See merge request !6181

By changing our logic from `before_transition` to `after_transition`
blocks and removing extra calls to `update` or `save` we can do all
changes in a single UPDATE query (currently each transition change
from started -> failed and started -> finished runs two UPDATE
queries each)

Use gitlab-workhorse 0.8.1

Adds Sentry support in gitlab-workhorse.

See merge request !6283

Avoid conflict with Admin labels when importing GitHub labels

If the GitHub project have duplicated labels from the Admin labels, the importer will use the Admin label.

Fixes #21319

See merge request !6158

This adds (basic) Sentry support.

Restore comments lost when converting CoffeeScript to JavaScript

## What does this MR do?

Restores comments lost in the great fire of !5464.

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

## Why was this MR needed?

#20300

## What are the relevant issue numbers?

 - #20300 (comments)
 - #20098 (ES6)

## 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 [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)
Closes #20300

See merge request !5541

Instrument more ES-related code

See merge request !721

Not sure why I missed this before. I thought I added it.