**Prevention of running 2 simultaneous updates**

Instead of using `RemoteMirror#update_status` and raise an error if
it's already running to prevent the same mirror being updated at the
same time we now use `Gitlab::ExclusiveLease` for that.

When we fail to obtain a lease in 3 tries, 30 seconds apart, we bail
and reschedule. We'll reschedule faster for the protected branches.

If the mirror already ran since it was scheduled, the job will be
skipped.

**Error handling: Remote side**

When an update fails because of a `Gitlab::Git::CommandError`, we
won't track this error in sentry, this could be on the remote side:
for example when branches have diverged.

In this case, we'll try 3 times scheduled 1 or 5 minutes apart.

In between, the mirror is marked as "to_retry", the error would be
visible to the user when they visit the settings page.

After 3 tries we'll mark the mirror as failed and notify the user.

We won't track this error in sentry, as it's not likely we can help
it.

The next event that would trigger a new refresh.

**Error handling: our side**

If an unexpected error occurs, we mark the mirror as failed, but we'd
still retry the job based on the regular sidekiq retries with
backoff. Same as we used to

The error would be reported in sentry, since its likely we need to do
something about it.

Only expire tag cache once per push

See merge request gitlab-org/gitlab-ce!31641

Rename comparer file for generic use

See merge request gitlab-org/gitlab-ee!15133

Geo - Remove feature flag for Docker container registries replication

Closes #2870

See merge request gitlab-org/gitlab-ee!15135

Return `429` instead of `302` on Rate Limiter on the raw endpoint

See merge request gitlab-org/gitlab-ce!31777

It was originally returning 302 when the rate limit kicks in, because
using the the correct status code makes it easier to track rate limiting
events

Related to https://gitlab.com/gitlab-org/gitlab-ce/issues/65974

Geo fully support replication for Docker container registries, and
the feature flag can be removed.

Backport of https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/14599

See merge request gitlab-org/gitlab-ce!31573

[Geo] Configure capacity for Docker sync service(3/4)

See merge request gitlab-org/gitlab-ee!14599

representing error message with .flash-container element

See merge request gitlab-org/gitlab-ce!31636

Merge branch '34414-update-personal-access-token-scope-descriptions-to-reflect-registry-permissions' into 'master'

Update personal access token api scope description

Closes #34414

See merge request gitlab-org/gitlab-ce!31759

EE 10161 hide issuable urls on vulnerability feedback

Closes #10161

See merge request gitlab-org/gitlab-ee!14928

Update links.md to give more consistency with the rest of the documentation

See merge request gitlab-org/gitlab-ce!31693

Add BrowserStack details to Frontend Dev Guide

See merge request gitlab-org/gitlab-ce!31744

Control the maximum concurrency of container repository
sync for a Geo node.

Part of Docker Regsitry Replication feature for Geo

Make cron notation parser a proper note

See merge request gitlab-org/gitlab-ce!31542

Previously each tag in a push would invoke the Gitaly `FindAllTags` RPC
since the tag cache would be invalidated with every tag.

We can eliminate those extraneous calls by expiring the tag cache once
in `PostReceive` and taking advantage of the cached tags.

Relates to https://gitlab.com/gitlab-org/gitlab-ce/issues/65795

Respect merge request block validations

Closes #13376

See merge request gitlab-org/gitlab-ee!15123

Only expire branch cache once per push

See merge request gitlab-org/gitlab-ce!31653

Change the language in the Licensing section

See merge request gitlab-org/gitlab-ce!29750

Change the language in the Licensing section - EE port

Closes gitlab-ce#55519

See merge request gitlab-org/gitlab-ee!11361

Move different licensing content from README to LICENSE file

Rename `timeouted?` to `timed_out?`

Closes #6796

See merge request gitlab-org/gitlab-ee!15124

Docs for self monitoring MVC

See merge request gitlab-org/gitlab-ce!31530

- The self-monitoring project can be connected to any Prometheus
instance. Make this more clear in the docs.