Consider removing project-specific semantics from descriptor package

[tmc]

Especially having openapi semantics in the descriptor package is suspect. I think it can (and should) be separate from the semantics from either the proxy generation and openapi generation. I think I made the first mistake here by merging #280

[ivucica]

This is unclear to me. #280 doesn't seem to relate to OpenAPI, and descriptor package doesn't seem to refer to OpenAPI either. Can you expand a bit on what OpenAPI semantics are you referring to?

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.