Updating examples to pydantic v2

[nsheff]

with pydantic 2, fastapi seems to have a new way to define examples using JSONschema.

In bedhost, there's actually a lot of complexity to the code around examples, and validation. I propose we scrap all the old code, introduce a requirement of python 3.10 + pydantic v2, and refactor all the examples and validation code to follow the new approach.

[khoroshevskyi]

I think, we can't use pydantic v2 at this point because we are using sqlmodel, which is based on pydantic v1, and there will be conflicts

[nsheff]

hm. good point, we might need to wait until sqlmodel is compatible with pydantic v2. I think it should happen in the next few months.

[nsheff]

To track SQLmodel update to pydantic 2: fastapi/sqlmodel#532

[nsheff]

Models can be updated now because sqlmodel has been updated to pydantic v2.