[JM-1278] Admins are now handled via a manager/provider structure, allowing for custom admin sources.
ClearspaceAdminProvider is a stub (not complete at this time).
Reviewer: Gabriel

git-svn-id: http://svn.igniterealtime.org/svn/repos/openfire/trunk@10171 b35dd754-fafc-0310-a699-88a17e54d16e