audit access permissions in rt.torproject.org

there are a lot of users in rt, some of which probably do not belong there:

https://rt.torproject.org/Admin/Users/

we need to perform an audit of who has access to RT, to which queue and clean all that up.

ideally, users shouldn't be granted individual access to stuff and only be part of groups which, in turn, have the required accesses.

users should also be added/removed properly as part of the onboarding/offboarding procedures, but that's a question for legacy/trac#32519 (moved). for now, this ticket is just about playing catchup.