feed extended class to validator

[Morriz]

Hi @MichalLytek, would it be possible to feed an extended class to the validator? I know applyModelsEnhanceMap takes a config object, but it would be awesome if it would be able to read a class with annotations. That way we can benefit from isomorphic validation:

1. add prisma-class-validator-generator generator
2. enhance classes with fine grained validators
3. use in frontend AND graphql server validation