"Request to Join Group" and similar functionality.

At the moment there is no good way a user can add themselves to a groups membership list. They must contact the owner who must add them via the group's Add Member form (and there is currently no way of reliably contacting the owner!).

A 'request to join' group system would be good. Presently all groups are private. Open-access groups are also a possibility (so a Join page). Need to look at these processes.