Users module should have more guidance

It looks like the users module is only described in this page:
https://directus.io/docs/guides/auth/creating-users

Although, most of the actions are only explained using API calls.

This should be improved by demonstrating how:
- a user can be created
- a user can be invited
- a user status can be changed
- a user can be archived
- a user can be deleted (including a notice that user may not be able to be deleted due to restrictive relationships)
- a user provider can be changed
- a user password can be changed
- a user email can be changed