kube-prometheus: add metrics-server example

manifests/metrics-server/auth-delegator.yaml

manifests/metrics-server/auth-reader.yaml

manifests/metrics-server/metrics-apiservice.yaml

...s/metrics-server/metrics-server-cluster-role-binding.yaml

manifests/metrics-server/metrics-server-cluster-role.yaml

manifests/metrics-server/metrics-server-deployment.yaml

manifests/metrics-server/metrics-server-service-account.yaml

manifests/metrics-server/metrics-server-service.yaml