Allow sorting groups in API

What does this MR do?

Allow groups to be sorted.

Are there points in the code the reviewer needs to double check?

I don't really like the helper methods, but it's probably OK for now.

Why was this MR needed?

We can't paginate the groups on the front-end if there's no sorting!

Does this MR meet the acceptance criteria?

• Changelog entry added
• Documentation created/updated
• API support added
• Tests
  • Added for this feature/bug
  • All builds are passing
• Conform by the merge request performance guides
• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?

Relates to #20013 (closed).