Add support for https://fastapi.tiangolo.com/ to Sentry Python SDK, and include in the new project onboarding.

• while there is not much added value to error handling (from a dedicated integration) compared to ASGI middleware
• there is a value add in performance
  • better transaction naming
  • better / contextual spans from the framework
• could hook into precise framework lifecycle events compared to general ASGI middleware wrapping