Pipeline variables expression in only/except configuration

What does this MR do?

This merge request adds support for pipeline variables expressions to only / except CI/CD configuration keywords.

It is a second part of the https://gitlab.com/gitlab-org/gitlab-ce/issues/37397, following https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/17261

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• Tests added for this feature/bug
• Review
  • Has been reviewed by UX
  • Has been reviewed by Product
  • Has been reviewed by Backend
• End-to-end tests pass (package-qa manual pipeline job)

What are the relevant issue numbers?

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/37397