This change modernizes the base classes for hosting services, primarily adding type annotations and correcting docstrings. The `authorize` and `check_repository` methods have been made keyword-only. These were already called by unpacking a dict, and in practice many of the individual implementations had inconsistent argument lists which would have made calling with positional arguments fail. The only places where we were using positional args were in a few unit tests, which have been updated. I've added `@deprecate_non_keyword_only_args`, but given the existing inconsistencies, we could probably do this change without a deprecation phase at all. Testing Done: Ran unit tests.