Clean up MongoHQHandler.
Replaced deprecated methods with new ones (mongo client 2.12)
MongoHQHndler: Not allowing access to getDB()
RatingsService: 
-Clean up 
-Switch to using getCollection instead of getDB
-MongoMQHandler:
- insert method with optional return _id
RatingsService: 
- Added full URL in response to post.
MongoHQHandler: Added findById
RatingsService: Get now uses findById