Update the REST spec with role draft features added in https://jira.ez.no/browse/EZP-24830.

Also, fix inconsistency: Originally there were different paths for actions on roles vs. on role drafts. The ID part of the path would refer either to the role or to the role draft.
Solution: Use only role paths. Ensure that when needed, the routes work correctly whether you supply a role ID or a role draft ID. As far as the REST user is concerned, it's all role IDs.