Overhauled typing and stub generation

[jmriebold]

Summary

At present, Oxyde's type hints indicate that Field returns an instance of OxydeFieldInfo (#13), and that queries return instances of Model rather than the defined class (#10). In addition, stub generation omitted fields from FKs. These three issues result in type checkers like Pyright and Ty flagging unknown attribute errors and type assignment errors in a codebase that uses Oxyde.

Changes

This PR does not change any core functionality, rather it updates the type hinting and stub generation to address the above issues. Specifically:

• Fixes Generic 'Model' type hints in Query/QueryManager break auto completion and mypy #10 by changing the return type hints to the model type being queried
• Fixes Type checker errors with Field() #13 by using pydantic_core.PydanticUndefined in place of pydantic.fields.PydanticUndefined (a Pydantic v2 API change)
• Adds filter params for FKs, including nested FKs, which matches documented functionality (note that these changes weren't extended to order_by() because it doesn't currently support ordering based on FK fields).

Testing

• All existing tests
• Migrated medium-sized CRUD API from Tortoise ORM to Oxyde to verify changes
  • with v0.7.0, Ty outputs 608 diagnostics
  • with this PR, Ty outputs 0 diagnostics

Notes

It'd probably be worth investigating why the existing type checks tests aren't catching these issues, since we know Mypy can flag them.

Thanks for an awesome library! Looking forward to migrating more projects over to it.