Add new NoDependencyContext

This marks dependencies for which we don't have any semantic
information.
Fix registration of internal dependencies
Add method `addSource` in Analysis and Relations

Both Analysis and Relations offered a method `addSource` that was
previously in charge of registering a source and adding its internal
dependencies, the external and binary dependencies were added later.

This method now accepts an internal source and all its dependencies,
from all kinds, that are immediately registered.