Generate typescript defintion files

Builder should be able to automatically generate typescript defintions for model.

This would greatly increase the DX when using Builder, and could probably done pretty easy.

I dont have any code examples currently, but for brevity a builder.get("event") could automatically be wrapped in a function - i.e MyBuider.getEvent() - which would call builder.get("event") and return a correctly defined interface - with all relations in play.