Move `User` model manipulation to RPC endpoint

[mathemancer]

Problem

One of our few remaining REST endpoints is /api/ui/v0/users/. Keeping that endpoint requires keeping around DRF, and in particular, requires keeping around our DRF error handling machinery. This adds an astonishing amount of complexity and code to our repo.

Proposed solution

We should move Mathesar user-wrangling functionality to RPC functions. The current list of endponts mapped to functions (from the wiki) is:

Endpoint	HTTP Method	Function
/api/ui/v0/users/{userId}/	DELETE	users.delete
/api/ui/v0/users/{userId}/	GET	users.get
/api/ui/v0/users/{userId}/	PATCH	users.patch
/api/ui/v0/users/{userId}/password_reset/	POST	users.password.revoke
/api/ui/v0/users/	GET	users.list
/api/ui/v0/users/	POST	users.add
/api/ui/v0/users/password_change/	POST	users.password.replace_own

Additional context

We elected to forgo moving these endpoints as part of the architectural transition to save time.

### Tasks
- [ ] https://github.com/mathesar-foundation/mathesar/issues/4000
- [ ] https://github.com/mathesar-foundation/mathesar/issues/4001
- [ ] https://github.com/mathesar-foundation/mathesar/issues/4002
- [ ] https://github.com/mathesar-foundation/mathesar/issues/4003
- [ ] https://github.com/mathesar-foundation/mathesar/issues/4004
- [ ] https://github.com/mathesar-foundation/mathesar/issues/4005
- [ ] https://github.com/mathesar-foundation/mathesar/issues/4006

[nilaygit-10721]

can you assign me this issue?

[mathemancer]

Hey @nilaygit-10721, this issue isn't quite ready for community contribution yet. I need to split it into a number of sub-tasks.

However, once I do that, you are welcome to try to solve one of the sub-tasks and submit a PR. We'll assign the issue for the sub-task you choose to you once you submit the PR, so no one else works on it while we're reviewing your work.

Thank you!

[nilaygit-10721]

okay @mathemancer thank you let me know when i can do that

[mathemancer]

@nilaygit-10721 Okay, I've specced out some issues.

Please submit PRs for each individual linked issue, and wait for the first to be reviewed before proceeding to the next.