generate column hints from nested Pydantic models

[rudolfix]

Background
With #2165 completed we can generate column hints for nested tables from Pydantic models. The goal is to modify make_hints and apply_hints to generate nested_hints containing column definitions found in nested Pydantic models.

Requirements

1. • modify or add a new function to pydantic.py that will recursively find nested tables (that correspond to lists of Pydantic models)
2. • use the above to generate nested hints (only columns I assume) in make_hints and apply_hints.
3. • if nested_hints are already provided, merge hints from Pydantic with provided hints (enough to replace columns)
4. • write tests and docs