Backport Cluster related EE code

What does this MR do?

Backports missing Cluster related code from EE.

EE counterpart: https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/5687

Does this MR meet the acceptance criteria?

• Review
  • Has been reviewed by Backend
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together
• End-to-end tests pass (package-and-qa manual pipeline job)

What are the relevant issue numbers?

Related https://gitlab.com/gitlab-org/gitlab-ee/issues/5968