ceph: adds scripts and components to support admission controllers

adds deploy.sh script to deploy validatingwebhookconfiguration and create secrets.
adds new command ceph admission-controller to start webhook servers.
adds validation for various rook custom resources

Signed-off-by: Vineet Badrinath <vbadrina@redhat.com>

tests/scripts/webhook-patch-ca-bundle.sh

@@ -0,0 +1,14 @@
+#!/bin/bash
+# Original script found at: https://github.com/morvencao/kube-mutating-webhook-tutorial/blob/master/deployment/webhook-patch-ca-bundle.sh
+
+set -o errexit
+set -o nounset
+set -o pipefail
+
+export CA_BUNDLE=$(kubectl get configmap -n kube-system extension-apiserver-authentication -o=jsonpath='{.data.client-ca-file}' | base64 | tr -d '\n')
+
+if command -v envsubst >/dev/null 2>&1; then
+    envsubst
+else
+    sed -e "s|\${CA_BUNDLE}|${CA_BUNDLE}|g"
+fi