[WIP] Enhance getPage in PageFactory

This is the first WIP commit, just a draft.
* Only the prefix logic is implemented and I am not sure  if the DefaultPageLocator should return an FQCN or a `Page` instance (in this case it requires a `PageFactory`).

Closes #12
I thought this is has something to do with mocking. But you can create any real classes you need in tests to test the resolver. No need to abstract that to separate method.