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>

deploy/nfs/kubernetes/csi-nfsplugin-provisioner.yaml

@@ -70,6 +70,20 @@ spec:
           volumeMounts:
             - name: socket-dir
               mountPath: /csi
+        - name: csi-snapshotter
+          image: registry.k8s.io/sig-storage/csi-snapshotter:v5.0.1
+          args:
+            - "--csi-address=$(ADDRESS)"
+            - "--v=5"
+            - "--timeout=150s"
+            - "--leader-election=true"
+          env:
+            - name: ADDRESS
+              value: unix:///csi/csi-provisioner.sock
+          imagePullPolicy: "IfNotPresent"
+          volumeMounts:
+            - name: socket-dir
+              mountPath: /csi
         - name: csi-nfsplugin
           # for stable functionality replace canary with latest release version
           image: quay.io/cephcsi/cephcsi:canary