Add and restructure external resources and examples

Closes #58041

See merge request gitlab-org/gitlab-ce!25588

Also refactors and combines resources and examples.

Clarify Rugged direct access only available in GitLab 11.9

See merge request gitlab-org/gitlab-ce!25887

Fixes split button styling in modal footers (CE port)

See merge request gitlab-org/gitlab-ce!25869

Allow skip trigger for gitlab:ui:visual

Closes gitlab-ui#198

See merge request gitlab-org/gitlab-ce!25894

By adding [skip visual] to the commit message the
gitlab:ui:visual test can be skipped.

This is needed to avoid deadlock situations as exhibited in
https://gitlab.com/gitlab-org/gitlab-ui/issues/198

Add missing keywords

Closes #51675

See merge request gitlab-org/gitlab-ce!25444

Also refactors structure of the page
to make the first section more useful.

Provide ee backports related to approver filtering

See merge request gitlab-org/gitlab-ce!25876

Adds custom validator for ArrayNoneAny param
Extracts some logic in js into separate files

Docs: Introduction to continuous methods and GitLab CI/CD

Closes #58394

See merge request gitlab-org/gitlab-ce!25611

- Pipeline status
- Job running
- Rollback button

Revert "Merge branch 'sh-show-pre-receive-error-merge' into 'master'"

See merge request gitlab-org/gitlab-ce!25895

This reverts merge request !25708

Upgrade Gitaly to v1.26.0

See merge request gitlab-org/gitlab-ce!25890

Merge branch '58304-extend-the-snowplow-event-tracking-documentation-with-a-testing-section' into 'master'

Resolve "Extend the "Snowplow event tracking" documentation with a "testing" section"

See merge request gitlab-org/gitlab-ce!25612

Created documentation for replying to comments

See merge request gitlab-org/gitlab-ce!25633

Unquarantine fixed tests

See merge request gitlab-org/gitlab-ce!25875

Fix "yarn-deduplicate has unmet dependencies"

See merge request gitlab-org/gitlab-ce!25885

Fix for mismatch in EE on FIXTURE_PATHS to FIXTURE_PATH

Closes gitlab-ee#10266

See merge request gitlab-org/gitlab-ce!25878

Display Ancestors in Issuable Sidebar

See merge request gitlab-org/gitlab-ce!25886

Resolve "Improve stop pipeline modal"

Closes #46464

See merge request gitlab-org/gitlab-ce!25059

Resolve "Project template for iOS"

Closes #58648

See merge request gitlab-org/gitlab-ce!25872

Until we solve https://gitlab.com/gitlab-com/gitlab-docs/issues/347,
let's just be explicit to avoid confusion.

Resolve "Hashed storage migration should not be attempted if project does not validate"

Closes #56618

See merge request gitlab-org/gitlab-ce!25753

Use date for upcoming milestone comparison

Closes #58325

See merge request gitlab-org/gitlab-ce!25806

Incremental backups

See merge request gitlab-org/gitlab-ce!24035

Adding additional usage metrics for Release to weekly ping

See merge request gitlab-org/gitlab-ce!25014

Resolve "Mask the existing variables"

Closes #58010

See merge request gitlab-org/gitlab-ce!25868

Remove translation dependency in CA spec

Closes #58653

See merge request gitlab-org/gitlab-ce!25882

Fix: https://gitlab.com/gitlab-org/gitlab-shell/merge_requests/280

Signed-off-by: Rémy Coutable <remy@rymai.me>