Changes to Repository docs for SSOT epic

See merge request gitlab-org/gitlab-ce!31075

Content about Repository was edited to comply with
docs standards. This is part of a SSOT epic.

- Added standard elements to each file.
- Moved content on Branches, and Compare, to the
  Branches file.
- Added a brief introduction piece to the GPG
  content.
- Lightly edited all content to improve clarity.

Merge branch '63547-add-system-notes-for-when-a-zoom-call-was-added-removed-from-an-issue' into 'master'

Resolve "Add system notes for when a zoom call was added/removed from an issue"

Closes #63547

See merge request gitlab-org/gitlab-ce!30857

Reorganize metrics dashboard

See merge request gitlab-org/gitlab-ce!31006

In preparation for embedding specific metrics in issues
https://gitlab.com/gitlab-org/gitlab-ce/issues/62971,
this commit moves the BaseService for metrics dashboards
to a new services subdirectory. This is purely for the sake
of organization and maintainability.

Resolve "Make quick action "commands applied" banner more useful"

Closes #56100

See merge request gitlab-org/gitlab-ce!26672

Extends the quick actions "commands applied" banner to show
the quick action preview text, but with everything in past tense.

EE Port: Make quick action "commands applied" banner more useful

See merge request gitlab-org/gitlab-ee!14630

Resolve "MembersFinder contains slow database query with OR conditions"

Closes #64180

See merge request gitlab-org/gitlab-ce!30451

Alerts dropdown to modal - EE1

See merge request gitlab-org/gitlab-ee!14760

Buttons and valid state go in there, so makes sense
for form to contain the modal

Alerts dropdown to modal - CE1

See merge request gitlab-org/gitlab-ce!31036

Resolve "Elasticsearch: restore global notes search"

Closes #11793

See merge request gitlab-org/gitlab-ee!14818

Add the execution_message text for all the EE only quick actions.

Extends the quick actions "commands applied" banner to show
the quick action preview text, but with everything in past tense.

Fix broken master because of security merge

Closes #65294

See merge request gitlab-org/gitlab-ce!31252

Update Rugged to 0.28.2

See merge request gitlab-org/gitlab-ce!31218

Removed duplicated section from CHANGELOG.md

See merge request gitlab-org/gitlab-ee!14897

Add a zoom link added / removed system note when a zoom link is being
added / removed to the issue description.

Change qa-merge-request-settings to rspec-merge-request-settings

Closes gitlab-org/quality/team-tasks#182

See merge request gitlab-org/gitlab-ce!31207

Change qa-* class references to js-* for suggestions

Closes gitlab-org/quality/team-tasks#182

See merge request gitlab-org/gitlab-ce!31213

Change qa-* class references to js-* for squash-checkbox

Closes gitlab-org/quality/team-tasks#182

See merge request gitlab-org/gitlab-ce!31214

Change qa-reverse-sort class references to rspec-reverse-sort

Closes gitlab-org/quality/team-tasks#182

See merge request gitlab-org/gitlab-ce!31202

Change qa-* class references to rspec-* in spec/features/contextual_sidebar_spec.rb

Closes gitlab-org/quality/team-tasks#182

See merge request gitlab-org/gitlab-ce!31211