This commit adds a database migration and ActiveRecord models to
represent the idea of a merge request that blocks another merge request
from being blocked.

There is no way to add a block through the UI yet, but you can create
them in the Rails console and observe that a merge request becomes
unmergeable as a result.

CE destroy repo mirrors

Closes #54574

See merge request gitlab-org/gitlab-ce!27087

It is important to destroy data related to repo mirrors when they are
disabled.
Use `_destroy` nested attribute instead of `enabled` for push mirrors.
Call `remove_import_data` after saving a project if its pull mirror is
disabled.

EE destroy repo mirrors

Closes gitlab-ce#54574

See merge request gitlab-org/gitlab-ee!10355

It is important to destroy data related to repo mirrors when they are
disabled.
Use `_destroy` nested attribute instead of `enabled` for push mirrors.
Call `remove_import_data` after saving a project if its pull mirror is
disabled.

Add some missing strings to locale/gitlab.pot

See merge request gitlab-org/gitlab-ee!12310

CI variables of type file

Closes #46806

See merge request gitlab-org/gitlab-ce!27112

Add env_var and file as supported types for CI variables. Variables of
type file expose to users existing gitlab-runner behaviour - save
variable value into a temp file and set the path to this file in an ENV
var named after the variable key.

Resolves https://gitlab.com/gitlab-org/gitlab-ce/issues/46806.

Port of 46806-typed-ci-variables to EE

See merge request gitlab-org/gitlab-ee!12280

Fix uploading of LFS tracked file through UI

Closes #61203

See merge request gitlab-org/gitlab-ce!28052

Move out EE context out of Gitlab::GitAccess spec

Closes #6660

See merge request gitlab-org/gitlab-ee!12130

[QA] Escape arg used as regex

Closes gitlab-org/quality/performance#2

See merge request gitlab-org/gitlab-ce!28104

Resolve "Reporters can create labels in projects/groups"

Closes #61222

See merge request gitlab-org/gitlab-ce!27991

Merge branch '10090-move-ee-differences-for-app-assets-javascripts-pages-projects-issues-index-index-js' into 'master'

Resolved EE differences for issues page index

Closes gitlab-ee#10090

See merge request gitlab-org/gitlab-ce!28031

Remove cleaned up OIDs from database and cache

Closes #30093

See merge request gitlab-org/gitlab-ce!26555

CE Backport: Create ActiveRecordModel and table for Merge Train feature

See merge request gitlab-org/gitlab-ce!27879

Merge branch '58105-pipeline-author-and-commit-author-too-close-together-in-pipeline-list' into 'master'

Improve pipelines table spacing, add triggerer column

Closes #38802 and #58105

See merge request gitlab-org/gitlab-ce!26136

Create ActiveRecordModel and table for Merge Train feature

See merge request gitlab-org/gitlab-ee!11204

Add client methods for DisconnectGitAlternates rpc

See merge request gitlab-org/gitlab-ce!27938

Port to EE: Fix duplicate merge request pipelines created by Sidekiq worker retry

See merge request gitlab-org/gitlab-ee!12212

Fix duplicate merge request pipelines created by Sidekiq worker retry

See merge request gitlab-org/gitlab-ce!26643

Session stored globally per request

See merge request gitlab-org/gitlab-ce!27658

Backport "Fix namespace/project removal elasticsearch limit" to CE

See merge request gitlab-org/gitlab-ce!27933

Fix namespace/project removal elasticsearch limit

Closes #11225

See merge request gitlab-org/gitlab-ee!11989

[CE] Fix filter token not showing up when multiple assignees are enabled

See merge request gitlab-org/gitlab-ce!27759

Fix filter token not showing up when multiple assignees are enabled

See merge request gitlab-org/gitlab-ee!11939

Assertions were made based on elements found so the specs
still pass even if the elements don't exist

Fix deleting of feedback comment author

Closes #11400

See merge request gitlab-org/gitlab-ee!11985