Merge code quality docs together

See merge request gitlab-org/gitlab-ce!32737

Bring the example config and the main doc together to simplify
documentation for code quality

Change several links to relative

See merge request gitlab-org/gitlab-ce!32919

Make several links, mostly in admin troubleshooting,
relative, as is the standard

Don't retry the review-* jobs since they're allowed to fail

See merge request gitlab-org/gitlab-ce!32893

Update docs for non member unresolving resolved thread

See merge request gitlab-org/gitlab-ce!32375

Do not include ApiHelpers again in spec/requests/api

See merge request gitlab-org/gitlab-ce!32870

Fix doc links for adding a cluster to a project

See merge request gitlab-org/gitlab-ce!32890

EE Port of Run pipeline button for "Pipelines for merge requests

See merge request gitlab-org/gitlab-ee!16378

In the Merge Request view, under pipelines tab
the user can see a run pipeline button

Adds axios post request to button click

Adds the logic to handle the user click,
refresh the table and disable the button while thee
request is being made

Updates UI for desktop and mobile

Adds specs
Regenerates potfile

Follow-up after review

Uses .finally to avoid code repetition

Fix wrong tier error message for Operations dashboard

See merge request gitlab-org/gitlab-ee!16319

The operations dashboard feature was brought from Ultimate to Premium
in GitLab 11.10
https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/10586.

This renames some missing items from Gold to Silver.

Resolve "Run pipeline button for "Pipelines for merge requests""

Closes #65940

See merge request gitlab-org/gitlab-ce!31722

In the Merge Request view, under pipelines tab
the user can see a run pipeline button

Adds axios post request to button click

Adds the logic to handle the user click,
refresh the table and disable the button while thee
request is being made

Updates UI for desktop and mobile

Adds specs
Regenerates potfile

Follow-up after review

Uses .finally to avoid code repetition

Optimize /admin/applications so that it does not timeout

Closes #67228

See merge request gitlab-org/gitlab-ce!32852

[Backend]  API for Step 2 of Trial

See merge request gitlab-org/gitlab-ee!15490

We need to create Leads when customers are requesting a trial for
GL.com. In order to do it we're going to use a service that will call a
custom endpoint on the subscription portal.

Add additional dirs to QA image Dockerignore

See merge request gitlab-org/gitlab-ce!32900

Optimize queries for snippet listings

See merge request gitlab-org/gitlab-ce!32576

Add instructions for defining stages

See merge request gitlab-org/gitlab-ce!32896

Geo: Docker Registry replication documentation (4/4)

Closes gitlab-ee#2870

See merge request gitlab-org/gitlab-ce!31196

Add the Upgrade button to the User Billings page

Closes customers-gitlab-com#518

See merge request gitlab-org/gitlab-ee!15075

Geo: Refactor file replication

See merge request gitlab-org/gitlab-ee!16382