Automatically merge CE master into EE master

See merge request gitlab-org/gitlab-ce!23453

update installation from source guide

See merge request gitlab-org/gitlab-ce!23516

CE port of Add new service to create the web ide terminal

See merge request gitlab-org/gitlab-ce!23514

[CE backport]Add sort direction button with sort dropdown for epics

See merge request gitlab-org/gitlab-ce!23506

Added a Hebrew proofreader

See merge request gitlab-org/gitlab-ce!21863

Fix multiple commits shade overlapping vertical discussion line

See merge request gitlab-org/gitlab-ce!23515

Fixes a typo that prevented assets from being properly compiled

Closes #54825

See merge request gitlab-org/gitlab-ce!23528

This updates the documentation of automatic CE to EE merges to cover the
new automatic merging setup.

This sets up GitLab CI to automatically push CE master changes into EE
master, or revert them if the changes cause merge conflicts. The CI
configuration contains a single job to do this: `merge:master`. This job
is executed for every push to master, and periodically using a CI
schedule.

The periodic job is necessary because incremental jobs may not be able
to revert commits if newly added commits depend on these commits. By
re-running the job periodically (including all changes since a large
enough time frame), we can ensure that such commits are also reverted
(if they still conflict at that time).

The job runs in its own "merge" stage, _after_ the build and prepare
stages, but _before_ running the tests. This ensures that randomly
failing tests won't prevent code from being merged into EE. Running the
stage after the "prepare" stage reduces the chances of the job reverting
CE changes just because it ran before a corresponding EE MR was merged
into EE master.

# Conflicts:
#   doc/development/i18n/proofreader.md

[CE] Backport TokenAuthenticatable comparison method and stub_default_url_options

See merge request gitlab-org/gitlab-ce!19094

Check the uniqueness of the values of pipeline enum

See merge request gitlab-org/gitlab-ce!23504

CE port Refactor Gitlab::Checks::ChangeAccess class

See merge request gitlab-org/gitlab-ce!23533

Fallback to admin KUBE_TOKEN for project clusters only

See merge request gitlab-org/gitlab-ce!23527

Fix collapsing discussion replies

Closes #54646

See merge request gitlab-org/gitlab-ce!23462

Revert "Merge branch 'auto-devops-support-for-group-security-dashboard' into 'master'"

See merge request gitlab-org/gitlab-ce!23530

CE Port2 of "Add empty and disabled web terminal tab"

See merge request gitlab-org/gitlab-ce!23509

Update -font-size variable name

See merge request gitlab-org/gitlab-ce!23519

Disable format determination based on path extension

Closes #54278

See merge request gitlab-org/gitlab-ce!23454

Make docs about expect_next_instance_of consistent

See merge request gitlab-org/gitlab-ce!23507

This reverts merge request !23165

Approximate table counts based on TABLESAMPLE

See merge request gitlab-org/gitlab-ce!22650

For CE on dev.gitlab.org

Fix lack of documentation on how to fetch a snippet's content using API

See merge request gitlab-org/gitlab-ce!23448

We do not want group level clusters to fall back to what was old
behaviour for project level clusters. So instead we will not return any
KUBE_TOKEN if we cannot find a suitable kubernetes_namespace for the
project, in the group level cluster case.

Add test cases to assert above

Fix documentation for /api/v4/projects/:id/repository/archive

Closes #45992

See merge request gitlab-org/gitlab-ce!23501

Rollback will not work because Envoy will still fetch latest commit from the…

See merge request gitlab-org/gitlab-ce!23493

Docs : Auto Devops migrate: add two release info

See merge request gitlab-org/gitlab-ce!23500

[ci skip]

The numbers in
https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/22650#note_117645395
are quite promising with that target.

This improves readability quite a bit.