Fix pipelines for merge requests does not show pipeline page when source branch   is removed

Closes #60432

See merge request gitlab-org/gitlab-ce!27803

Source branch can be removed after the merge and
we have to make sure to avoid rendering links if it's the case.

Regenerate gitlab.pot file

See merge request gitlab-org/gitlab-ee!11933

Docs: Add intro and reorg CI index

Closes #58323

See merge request gitlab-org/gitlab-ce!27620

Plus: add note for .com users

Merge branch '60476-actionview-missingtemplate-missing-template-projects-issues-_merge_requests-with-locale-en-formats-html-varian' into 'master'

Delete leftover code for referenced_merge_requests endpoint

Closes #60476

See merge request gitlab-org/gitlab-ce!27335

Propagate ENV vars to SAST and Dependency Scanning Docker containers only if they are set

See merge request gitlab-org/gitlab-ee!11523

This reverts commit 0c4a25f3, reversing
changes made to 6513028e.

This reverts commit cfed90dc, reversing
changes made to a1e84c1a.

Explicityly require `gl_repository` in internal api spec.

Closes #11387

See merge request gitlab-org/gitlab-ee!11900

Explicitly requiring `Gitlab::GlRepository` in the spec that requires
it makes sure it is correctly prepended with
`EE::Gitlab::Repository`.

Otherwise, if a spec before it autoloaded one of the constants from
within `Gitlab::GlRepository` the module would not be prepended.

Fixed boards card dragging styling

Closes #61050

See merge request gitlab-org/gitlab-ce!27802

Extract EE specific files/lines for Discussion spec/requests/api

Closes #6670

See merge request gitlab-org/gitlab-ee!10603

Regenerate locale/gitlab.pot file

See merge request gitlab-org/gitlab-ee!11896

Fix base domain help text update

Closes #61036

See merge request gitlab-org/gitlab-ce!27746

Internationalisation of javascript/m* directories

See merge request gitlab-org/gitlab-ce!27723

This is one of many MRs opened in order to improve the overall
internationalisation of the GitLab codebase.

i18n documentation
https://docs.gitlab.com/ee/development/i18n/externalization.html

Internationalisation of vue_shared directory

See merge request gitlab-org/gitlab-ce!27751

This is one of many MRs opened in order to improve the overall
internationalisation of the GitLab codebase.

This commit only targets the Vanilla JS files.

i18n documentation
https://docs.gitlab.com/ee/development/i18n/externalization.html

Update dependency @gitlab/ui to ^3.7.0

See merge request gitlab-org/gitlab-ce!27832

Resolve "Project is being serialized when enqueueing to sidekiq"

Closes #59265

See merge request gitlab-org/gitlab-ce!27825

Prevent concurrent execution of PipelineScheduleWorker

Closes gitlab-com/gl-infra/production#805

See merge request gitlab-org/gitlab-ce!27781

Change comments to point to the new path of sidekiq-cluster

See merge request gitlab-org/gitlab-ce!27707

Move sidekiq-cluster to ee/bin

Closes #6565

See merge request gitlab-org/gitlab-ee!11001

Upgrade letter_opener_web to support Rails 5.1

See merge request gitlab-org/gitlab-ce!27829

Before this commit using `/rails/letter_opener` in `development`
environment failed with:

    undefined method `before_filter'

See https://github.com/fgrehm/letter_opener_web/issues/68

This commit upgrades `letter_opener_web` to 1.3.4 so Rails 5.1 is
supported.

Resolve "Extract EE specific files/lines for spec/javascripts/vue_mr_widget/mock_data.js"

Closes #6553

See merge request gitlab-org/gitlab-ee!11847

- Regular mock_data is the same in CE and EE now
- new EE-specific mock_data extends the CE one
- Updated dependent specs in EE