New Constant

[thehabes]

Dev and Prod rerum_servers are going to use the same mongo instance on the same server now. Now what will change is the name of the collection to use from the mongo connection. We will have the collection annotationStore for production. We will have annotationStoreDev for development.

This "mongodb-to-use" should become a Constant in rerum_server. Constant.java could use a small cleanup while in there.