Allow updating and deleting Organization Users

[Fodoj]

Organization users are one of these resources that you cannot create but you can modify and delete.

I think it's still worth having a resource with the caveat that you need to first import the resources by using a data resource, and after that, you can actually manage the entries just fine.

Alternatively, this new resource can also work without any data resource:

1. "creation" process just checks if the user exists on the API side
2. if it does, it gets saved to the state and can be updated and deleted as needed
3. if it doesn't, "creation" fails

Naturally, to do this you need to know user's ID.

We can think about adding "creation" by just specifying the email in the future.