Add InferTypeOpTrait & enable generating its member function definition

Use OpInterfaces to add an interface for ops defining a return type function.

This change does not use this trait in any meaningful way, I'll use it in a
follow up to generalize and unify some of the op type traits/constraints. Also,
currently the infer type function can only be manually specified in C++, that should rather be the fallback in future.

PiperOrigin-RevId: 271883746