Can you add `depth` feature?

[KDH]

I think that the depth is a useful feature when serializing the model has many relationships like the DRF serializer's depth option

Other libraries that it has depended on Pydantic

• https://github.com/vitalik/django-ninja/blob/master/ninja/orm/factory.py#L29

[KDH]

I close this issue because I think this feature is not useful in SQLAlchemy