XD-1077: Tweaks to ResourceModuleRegistry

The main idea is to be more flexible still about the location of
modules. To pave the way for that I wan to switch to resource 
pattern as root for module instead of a Resource (which is really the
wrong abstraction since we have to do a pattern search anyway).
The main benefit of this will be that we can use classpath*: as a module
root prefix, and pick up contributions from multiple classpath
locations at once.