feat/Add new cli to generate schema as yaml

[rbiseck3]

Description

Initial introduction of new etl-schema that takes the same pointers to a python function as etl-uvicorn and prints the generated schema as yaml to populate in a manifest for a given plugin. This can be updated to support writing output to a yaml file.

Example:

pip install .
PYTHONPATH=. etl-schema test.assets.typed_dict_response:sample_function
inputs:
  properties:
    content:
      properties:
        name:
          type: string
        value:
          type: number
      required:
      - name
      - value
      type: object
  required:
  - content
  type: object
outputs:
  properties:
    response:
      type: object
  required:
  - response
  type: object

[hubert-rutkowski85]

Nitpick: there is no obvious relation between sample_function stored in test.assets.typed_dict_response.py, and expected_results/simple.yaml . Naming it like expected_results/typed_dict_response:sample_function.yaml would make it painfully clear, unfortunately it's a mouthful. Maybe it's ok, or maybe just using the filename, or a function name, would be good enough. I'll leave it for you to decide, to not keep this PR waiting any longer.