deploy: add support for nfs snapshot

This commit add external-snapshotter container and
required rbac to support nfs snaphots.
Example volumesnaphotclass, volumesnapshot,
pvc-restore and pod-restore yamls are also added.

Signed-off-by: Rakshith R <rar@redhat.com>

examples/nfs/pvc-restore.yaml

@@ -0,0 +1,16 @@
+---
+apiVersion: v1
+kind: PersistentVolumeClaim
+metadata:
+  name: nfs-pvc-restore
+spec:
+  storageClassName: csi-nfs-sc
+  dataSource:
+    name: nfs-pvc-snapshot
+    kind: VolumeSnapshot
+    apiGroup: snapshot.storage.k8s.io
+  accessModes:
+    - ReadWriteMany
+  resources:
+    requests:
+      storage: 1Gi