Prepare DBTrans class for dependency injection

[jpaugh]

TODO: Test to avoid exceptions

• Implement a new interface IDBTrans
• Ensure all callers are using the interface instead of the implementation class.
• Instantiate DBTrans using try-with-resources.
• Allow DBTrans to control the lifetime of its own SQL Connection, and to share the same connection (implicitly) across all methods
• Remove connection parameter from all methods of IDBTrans.
• Allow DBTrans.createDB to control the lifetime of its own SQL Statement, and remove it from the parameters.
• Build fixes for gradle and IntelliJ IDEA on my system

[jpaugh]

Fred made incompatible changes to DBTrans, and besides, this is his project. I guess I got a little too excited. :-)