Automatic merge from submit-queue
move constants to their own file
A step towards #44065
These constants are part of the API and will be moved to k8s.io/api. The helper functions are not and will remain in the main repo. This PR separates them to different files. Next step is put all the helper functions into sub-packages, so that the package `k8s.io/kubernetes/pkg/api` only contains code we want to move to k8s.io/api.
I added the retest-not-required label because this just moves code to another file in the same package.
d8fbff35cd