Move ResourceLoader classes to their own namespace. Strip the
"ResourceLoader" prefix from all except ResourceLoader and
ResourceLoaderContext.
Move the tests by analogy.
I used a namespace alias "RL" in some callers since RL\Module is less
ambiguous at the call site than just "Module".
I did not address DependencyStore which continues to have a non-standard
location and namespace.
Change-Id: I92998ae6a82e0b935c13e02a183e7c324fa410a3
e08ea8ccb9