XD-713 @Configuration modules!

Adds support for JavaConfiguredModule. ModuleFactoryTests loads an uberjar built as a separate project. The module project zip is also included for reference. 

2nd commit addresses XD-1085 (groovy modules) - added to this PR because I updated ModuleFactoryTests which is new in this branch.
I agree with David here. This is consistent with what users expect. If we forced a single class as the entry point, then anyone wanting to include more beans would need to add explicit import annotations, and that would be different than how they would use the configuration class in any other Spring context.