Only make Review App deployment automatic for frontend changes

What does this MR do?

This makes Review App deployment and smoke end-to-end run against them automatic for frontend-related changes, and manual otherwise.

For non-frontend changes, people should just have to start the review-build-cng job and the job would automatically play the review-deploy job once finished (e.g. https://gitlab.com/gitlab-org/gitlab/-/jobs/477627203), and the review-deploy job would do the same and automatically play the review-qa-smoke and review-performance jobs once finished.

Does this MR meet the acceptance criteria?

Conformity

• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Separation of EE specific content

Closes #208834 (closed).