Separate Permissions for each machine

[slominskir]

It would be optimal if permissions can be stored/updated separately for each machine. When changes are made users must carefully study the new permissions to see what has changed and some users are only interested in a particular machine, which may not have been updated at all. Initially the beam authorization app was designed for just the CEBAF machine, but over the years we've bolted on LERF and UTIF as well. We may want to separate credited controls and beam destinations as well.