Add selective e2e test execution for review app

What does this MR do and why?

Describe in detail what your merge request does and why.

Adds selective test execution to review-app.

• Implements https://gitlab.com/gitlab-org/quality/team-tasks/-/issues/1395+
• Partially fixes package-and-qa job does not auto run based on M... (#366871 - closed) in scope of review-app tests
• Simplifies job structure and test reports, uses more generic terms in names to clearly state which jobs are blocking merge and which are not

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Test runs

• single spec change, executes single test job: https://gitlab.com/gitlab-org/gitlab/-/pipelines/634783893
• single orchestrated spec change, tests not executed: https://gitlab.com/gitlab-org/gitlab/-/pipelines/634963345
• framework changes, execute all specs: https://gitlab.com/gitlab-org/gitlab/-/pipelines/634875606
• backend change, manage label: execute full blocking suite and only manage specific additional specs: https://gitlab.com/gitlab-org/gitlab/-/pipelines/635054399