Automatic merge from submit-queue (batch tested with PRs 44569, 44398)

Move v1/refs and v1/resource

This PR moves pkg/api/v1/ref.go and pkg/api/v1/resource_helper.go to their own sub packages, it's very similar to 44299 and 44302.

The PR is mostly mechanical, except that 
* i moved some utility function from resource.go to pkg/api/v1/pod and pkg/api/v1/node, as they are more appropriate
* i updated the staging/copy.sh to copy the new subpackages, so that helper functions are copied. We can get rid of this copy after client-go stops copying API types.