A debug tool that collects resources from api server and compares it
with the scheduler cache. It currently only compares the node list, but
it should be easy to extend. The compare is triggered by signal USER2,
by doing
kill -12 ${SCHED_PID}
The compare result goes to scheduler log.
Towards #60860
This moves plugin/pkg/scheduler to pkg/scheduler and
plugin/cmd/kube-scheduler to cmd/kube-scheduler.
Bulk of the work was done with gomvpkg, except for kube-scheduler main
package.
