Add common customizations to the documentation site
Problem/Motivation
After watching part of this presentation (the one focused on GitLab CI): https://youtu.be/c6hg5sEE8Sg?feature=shared&t=1347
It lasts around 12 minutes (minute 22 to minute 34) and covers some great examples, so maybe we can add those examples to our https://project.pages.drupalcode.org/gitlab_templates/info/common/ or https://project.pages.drupalcode.org/gitlab_templates/info/customizations/ sections.
Slides: https://berdir.github.io/drupalorg-workflows/ (move to slide 34 and then navigate down)
Proposed resolution
Update documentation:
* Tweaks to existing jobs
* Custom images
* Setting some jobs as manual
* ...
Remaining tasks
MR against the "docs" folder
Edited by drupalbot