Add pydantic v2 support with backwards compatibility

[aaliboyev]

Here I tried to add support for pydantic v2 BaseModel and Field.

This solution theoretically (we cover with tests once maintainers approve this implementation) work with any pydantic package.
I tested it with real project and these packages seems to be working with simple Item model.
pydantic<1.10 - Before new BaseModel
pydantic>=1.10.17 - In the migration guide they mention this exact version where they moved old BaseModel under pydantic.v1 namespace

Similarly I tried to move v1 specific adapter and model under pydantic_v1 and used pydantic for new version.
I also tried to include all Field attributes to metadata and of course if some of them don't work fine we can remove or workaround.
If this implementation is acceptable I will try to add some tests and docs. Let me know what we can adjust.

Fixes #72