feat(ogroup) Detect member types from subgroups

This means a group of group of users will have user tabs.
This is not dynamically updated when editing a member, meaning if group1
 contains group2 which contains users, removing all users from group2
 will not update group1 gosaGroupObjects field, which will still
 contain U until group1 is open and saved.
This seems like a small problem as most of the time this type detection
 is mainly useful to know which tabs to show, so when the object is
 open.
It may be added later.

issue #5818