feat: Expose annotations for structs and services

[kevin-greene-ck]

@rbattala-ck I know you're probably not that familiar with this code yet, but if you could just give this a sanity check it would be much appreciated. I need to update some of the test fixtures to have empty annotations, but the logic should be ready.

[kevin-greene-ck]

This isn't handling services that extend other services yet. A service should inherit annotations.