DefaultRepositoryFactory: single repository for aliased entities

The actual implementation of ``DefaultRepositoryFactory`` create multiple instances for a single entity if is accessed by multiple namespace aliases.

I've patched ``DefaultRepositoryFactory::getRepository`` so that aliases are resolved before saving the reference into the ``repositoryList``.

Just to not affect performance of existing implementation, I've added to the ``repositoryList`` both the aliased class name and the fully-qualified class name, but only the latter is required.


The optimization can be skipped entirely here IMO - if we always rely on the real metadata name, we're pretty much fine.