Add docs on how web terminals are secured

Closes #52681

See merge request gitlab-org/gitlab-ce!24099

CE backport of gitlab-ee!8936

See merge request gitlab-org/gitlab-ce!23976

Link highlighting of jon.doe@example.com swallowed the trailing backtick, destroying formatting.

See merge request gitlab-org/gitlab-ce!24133

Document new incoming email address format

See merge request gitlab-org/gitlab-ce!23991

Hashed Storage: Only set as `read_only` when starting the per-project migration

See merge request gitlab-org/gitlab-ce!24128

Fix doc for "Allow getting the merge base of multiple revisions"

See merge request gitlab-org/gitlab-ce!24051

Import issues from CSV

Closes #49231

See merge request gitlab-org/gitlab-ce!23532

In the previous code, we locked the project during the migration
scheduling step, which works fine for small setups, but can be
problematic in really big installations.

We now moved the logic to inside the worker, so we minimize the time a
project will be read-only. We also make sure we only do that if
reference counter is `0` (no current operation is in progress).

Fix QA spec sharing project in the wrong context

Closes gitlab-org/quality/nightly#54

See merge request gitlab-org/gitlab-ce!24183

Externalize strings from `/app/views/shared/notes`

See merge request gitlab-org/gitlab-ce!23696

CE port: Use parent instead of project for quick actions

See merge request gitlab-org/gitlab-ce!24124

Resolve "Sentry Configuration"

See merge request gitlab-org/gitlab-ce!23724

Avoid redirected Geo links

See merge request gitlab-org/gitlab-ce!24138

Use Container Scaning report fixture from EE

See merge request gitlab-org/gitlab-ce!23836

Add threshold lines in metrics graph

Closes #54978 and #56021

See merge request gitlab-org/gitlab-ce!24169

Re-use operations controller which already handles tracing settings.

Add support for group entities to quick actions

Add table and model for error tracking settings

See merge request gitlab-org/gitlab-ce!24047

In the administration page for web terminals add a new `Security`
section explaining how the interactive web terminals are secured between
GitLab and gitlab-runner.

This section is under administration instead of
`doc/ci/interactive_web_terminal` because the administrators of the
GitLab instance would be mostly interested in this, whilst
`doc/ci/interactive_web_terminal` are interested in how the feature
works.

closes https://gitlab.com/gitlab-org/gitlab-ce/issues/52681

Resolve "Ctrl+Enter immediately adds MR comment"

See merge request gitlab-org/gitlab-ce!24053

Resolve ""About this feature" link should open in new window"

Closes #55192

See merge request gitlab-org/gitlab-ce!24149

Document Auto DevOps secret variables

See merge request gitlab-org/gitlab-ce!23970

Externalization for pipeline tags

Closes #55721

See merge request gitlab-org/gitlab-ce!24028

Update to Vue 2.5.21

Closes #55592

See merge request gitlab-org/gitlab-ce!23969

Merge branch '53796-discard-draft-comment-button-to-easy-to-accidentally-hit-on-mobile' into 'master'

Resolve "Discard draft comment button to easy to accidentally hit on mobile"

Closes #53796

See merge request gitlab-org/gitlab-ce!24185

Update Releases documentation

Closes #55934

See merge request gitlab-org/gitlab-ce!24160