Make review apps pipeline rules self-contained

Some of the rules we can move into .gitlab/ci/review-apps/rules.gitlab-ci.yml directly, however some of them stayed in .gitlab/ci/rules.gitlab-ci.yml because they use some of the definitions only defined over there. We ended up with mixtures and it's a bit confusing.

Let's make this fully self-contained, and duplicate definitions if we have to.

The following discussion from !111047 (merged) should be addressed:

• @rymai started a discussion:

  suggestion: Should we move this to .gitlab/ci/review-apps/rules.gitlab-ci.yml?