Automatic merge from submit-queue
refactor genericapiserver new to combine initialization
Combines `New` and `init` since the two were inseparable before anyway. `New` now has all the code to create the `GenericAPIServer`.
The rest of the change is a move. I want to refactor the flow more, but I figured that doing it separately would simplify the review.
@sttts how do you feel about looking at this one?