Refactor workspace graphql fields

Issue: Backend: Refactor workspace graphql fields (#429891 - closed)

What does this MR do and why?

See detailed description in Backend: Refactor workspace graphql fields (#429891 - closed)

See overview of Category:Remote Development Workspaces Admin UI issues and MRs in MVP of Admin UI for Workspaces (&11992 - closed)

Screenshots or screen recordings

N/A, no UI changes.

How to set up and validate locally

All tests should pass, manual exploratory testing of creating and updating a workspace should still work.

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.