MCPServer: replace databaseInterface with Django models

`databaseInterface` is still imported in a few places in MCPServer, primarily for the `getUTCTime` function that will be moved elsewhere, and for database locking that may be removeable.
I think this is actually a BooleanField (or NullBooleanField).  Django's BooleanField [maps to tinyint](http://stackoverflow.com/questions/1778948/boolean-fields-in-mysql-django-models).