Automatic merge from submit-queue

move more things to apiserver

```
pkg/genericapiserver/api/handlers/negotiation/ -> apiserver/pkg/handlers/negotiation
pkg/genericapiserver/api/metrics -> apiserver/pkg/metrics
pkg/genericapiserver/api/request -> apiserver/pkg/request
pkg/util/wsstream -> apiserver/pkg/util/wsstream
plugin/pkg/auth/authenticator/request/headerrequest -> apiserver/pkg/authentication/request/headerrequest
plugin/pkg/webhook -> apiserver/pkg/webhook
```

and mechanicals.

`k8s.io/kubernetes/pkg/genericapiserver/routes/data/swagger` needs to be sorted out.