Provide a Kcl schema export

[samuel-deal-tisseo]

Feature Request

Is your feature request related to a problem? Please describe:

I'm creating my Iac tooling using kcl for my schema definition and source of truth.
I'm using a lot of python, and I would like to generate dataclasses from kcl schemas files in order to get a kind of string type for my scripts.

Describe the feature you'd like:
It would be nice to be able to run kcl export-schemas to generate json-schema.
To be able to generate those schemas from SDKs would be nice too.

Describe alternatives you've considered:
I tried the python SDK API().parse_program(...).ast_json tooling, but I don't want to rely on an unstable format. Also It feels like re-inventing the wheel when there is tools to ingest json-schemas

Teachability, Documentation, Adoption, Migration Strategy:
Documenting this feature should be nice

[Peefy]

Yes, we have already implemented this feature in the KCL Go SDK. For the CLI, you can use kcl doc gen --format openapi to export KCL schema