Refactor Recap types so aliases aren't global

[criccomini]

recap.types.RecapType uses a global static singleton for its type_registry. This gets in the way when parsing schemas that are unrelated. I'd rather have the aliases be managed separately (maybe at the converter level?).

[criccomini]

As part of this issue, test_protobuf.py should be updated so that Test1, Test2, Outer1, Inner1, etc are all renamed to Test, Outer, and Inner.