Drop QueueCaller database table

Change-Id: I428cca1f65cb105451e9fe51108be47554f5c6b1
Signed-off-by: Paul Belanger <paul.belanger@polybeacon.com>
Revert: Move QueueMember API into middleware

After discussion with Juggie, the majority of this configuraiton does
belong in the database.  For example, this will allow a supervisor to
setup Queue assignments for Agents.

Change-Id: Ic65ea7c71723afeafe547be5661e80e587bd5078
Signed-off-by: Paul Belanger <paul.belanger@polybeacon.com>