Agent - Add Backend Capabilities

*Create a Base Backend
*Call into it on NOTIFY, CREATE, DELETE events
*Port a Bind9 Backend

Change-Id: I730e666bbd9db48d1f6793f8f6b48decaee39cb9
WIP - Experimental Agent Pool Manager Backend

Change-Id: I390dbc5130eee40fb1bebae5666472f105ba2438