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.
Add an import-boss file to inventory what kubectl depends on, so
we can prune this list over time and eventually get kubectl out
of the main k/k repository.
To update this list, You can list the dependencies using:
go list -f '{{ join .Deps "\n"}}' k8s.io/kubernetes/cmd/kubectl | grep
k8s.io/kubernetes | grep -v kubectl | grep -v vendor
Add the generated list of package names to .import-restrictions
file. Then run the hack/verify-import-boss.sh until you have you have
all the packages needed.
