Allow complete deletion of groups.
Groups can be deleted simply and without problems. Initially, deletion should not have an audit trail and it should not be possible to undelete a group. Audit trail will become an objective (outside of this design doc) once the initial implementation is finished. In terms of the undelete operation it can be achieved by group re-creation under the original name.
Some hosts, especially those that are around for quite a long time, have many groups that are no longer used at all. There is currently no way to completely delete a group and that means that the host keeps an unnecessarily high number of refs. Also, it is a nuisance for the user to see so many different groups, when most of those are unused.