Automatic merge from submit-queue (batch tested with PRs 40003, 40017)

k8s.io/apiserver and genericapiserver: move packages around

Towards more sane k8s.io/apiserver package structure:

```
rename pkg/genericapiserver/{ => server}
 rename pkg/genericapiserver/{ => server}/filters
 rename pkg/genericapiserver/{ => server}/mux
 rename pkg/genericapiserver/{ => server}/openapi
 rename pkg/genericapiserver/{ => server}/options
 rename pkg/genericapiserver/{ => server}/routes
 rename pkg/genericapiserver/{ => server}/routes/data
 rename pkg/genericapiserver/{ => server}/routes/data/swagger
 rename pkg/genericapiserver/{api => endpoints}
 rename pkg/genericapiserver/{api => endpoints}/filters
 rename pkg/genericapiserver/{api => endpoints}/handlers
 rename pkg/genericapiserver/{api => endpoints}/handlers/responsewriters
 rename pkg/genericapiserver/{api => endpoints}/openapi
 rename pkg/genericapiserver/{api => endpoints}/testing
 rename pkg/genericapiserver/{api => registry}/rest
 rename pkg/genericapiserver/{api => registry}/rest/resttest
 rename pkg/{ => genericapiserver}/registry/generic
 rename pkg/{ => genericapiserver}/registry/generic/registry
 rename pkg/{ => genericapiserver}/registry/generic/rest
 rename staging/src/k8s.io/apiserver/pkg/{ => endpoints}/handlers/negotiation
 rename staging/src/k8s.io/apiserver/pkg/{ => endpoints}/metrics
 rename staging/src/k8s.io/apiserver/pkg/{ => endpoints}/request
 rename staging/src/k8s.io/apiserver/pkg/{ => server}/healthz
 rename staging/src/k8s.io/apiserver/pkg/{ => server}/httplog
 rename staging/src/k8s.io/apiserver/pkg/{ => util}/webhook
```