Revise logic of dependency caching, add cache key, make before script global.

Update the template showing how to cache restored dependencies, add few variables, reduce before_script part, add and improve descriptions.

Refactor params for NotesActions

Closes #54924

See merge request gitlab-org/gitlab-ce!25278

Removes unneeded params from permitted list

This also fixes commenting on commits with a hash starting with a large
number

Docs serverless updates

See merge request gitlab-org/gitlab-ce!25497

Merge branch '58062-tracing-url-template-render-using-string-format-does-not-play-well-with-urls' into 'master'

Switch back to using regexps in tracing_url_template

Closes #58062

See merge request gitlab-org/gitlab-ce!25491

Merge branch 'docs-serverless-updates' of gitlab.com:gitlab-org/gitlab-ce into docs-serverless-updates

Docs: add details about restricted SSH keys

Closes #50489

See merge request gitlab-org/gitlab-ce!25478

Add an index page to admin area section

Closes #55234

See merge request gitlab-org/gitlab-ce!25375

Resolve "/admin/runners page fails with an SQL Statement Timeout"

Closes #53325

See merge request gitlab-org/gitlab-ce!25220

Lower the allowed Gitaly call count to 30

See merge request gitlab-org/gitlab-ce!25467

Prior to this change, 35 Gitaly RPCs were allowed. But recently there's
been a renewed interest in performance. By lowering the number of
calls new N + 1's will pop up.

Later commits will add blocks to ignore the raised errors, followed by
an issue for each to be fixed.

Ensure all lists are surrounded by new lines

See merge request gitlab-org/gitlab-ce!25479

Markdown renderers find it easier to determine
where lists start and end when lists are surrounded
by new lines.

For consistency, also ensure entries in the list
are aligned when they span multipls lines.

This approach is able to cope with `%` characters in the URL template,
which is important since `%` is a valid URL character. Additionally
this approach is less likely to fail on an invalid string. This is
important since the distributed tracing infrastructure is designed to
degrade gracefully when not properly configured, and a small mistake
in the configuration of the URL template could have led to a production
outage.

Tracing URL templates should be able to include % characters. This test
is intended to show that the current implementation needs rework in
order to handle this requirement.

Improve snippets empty state

Closes #44045 and #20847

See merge request gitlab-org/gitlab-ce!18348

Only show borders around markdown images in notes

Closes #55703

See merge request gitlab-org/gitlab-ce!25448

Resolve "Fix danger commit messages check"

Closes #58057

See merge request gitlab-org/gitlab-ce!25489

Update dependency @gitlab/svgs to ^1.54.0

See merge request gitlab-org/gitlab-ce!25488

Port EE System Header And Footer feature to CE

Closes #55057

See merge request gitlab-org/gitlab-ce!25241

Resolve "Units are appended to Y axis label on metrics dashboard"

Closes #56477

See merge request gitlab-org/gitlab-ce!25485

Remove duplicate units from metrics dashboard graphs