text: Title: ModelSchema with lower camel case results?
  Body: **Is your feature request related to a problem? Please describe.**
  
  I have Django models that are snake case, as is traditional (e.g., full_name). The client already specified lower camel case (e.g., fullName). So, every API call I have, I want to use lower camel case.
  
  **Describe the solution you'd like**
  
  I'd like to be able to use alias_generator=to_lower_camel.
  
  This sort of code does not currently work for me:
  
  ```
  from pydantic.utils import to_lower_camel
  
  from .models import MyObj
  from ninja import ModelSchema
  
  class MyObjSchema(ModelSchema):
      class Config:
          model = MyObj
          model_fields = ["id", "name", "full_name"]
          # make names lower camel case
          alias_generator = to_lower_camel
  ```
  
  It results in `full_name: null` in all the results. If I comment out the alias_generator, it returns `full_name` populated, so I know this is the alias_generator.
  