py2http (and http2py and ecosystem) refactor ideas.

[thorwhalen]

• study state-of-art significantly before (FastAPI, pydantic, ...)
• Use i2's ingress and egress for wrapping endpoints (including input/output mappers (routing))
• include all REST request methods (py2http only supports POST, because was intended to only be used with http2py and http2js)
• Ensure validity of output openapi spec
• focus on a single (or two) target (and either do sync, or do async)
  • Just use FastAPI (the current favorite) for starters, trying to facade a minimum