deploy: remove psp from cephcsi

as PSP is deprecated in kubernetes 1.21
and will be removed in kubernetes 1.25
removing the existing PSP related templates
from the repo and updated the required documents.

fixes #1988

Signed-off-by: Madhu Rajanna <madhupr007@gmail.com>
(cherry picked from commit 96a3aabe5a)

examples/kms/vault/vault-psp.yaml

@@ -1,47 +0,0 @@
----
-apiVersion: policy/v1beta1
-kind: PodSecurityPolicy
-metadata:
-  name: rbd-csi-vault-token-review-psp
-spec:
-  fsGroup:
-    rule: RunAsAny
-  runAsUser:
-    rule: RunAsAny
-  seLinux:
-    rule: RunAsAny
-  supplementalGroups:
-    rule: RunAsAny
-  volumes:
-    - 'configMap'
-    - 'secret'
-
----
-kind: Role
-apiVersion: rbac.authorization.k8s.io/v1
-metadata:
-  # replace with non-default namespace name
-  namespace: default
-  name: rbd-csi-vault-token-review-psp
-rules:
-  - apiGroups: ['policy']
-    resources: ['podsecuritypolicies']
-    verbs: ['use']
-    resourceNames: ['rbd-csi-vault-token-review-psp']
-
----
-kind: RoleBinding
-apiVersion: rbac.authorization.k8s.io/v1
-metadata:
-  name: rbd-csi-vault-token-review-psp
-  # replace with non-default namespace name
-  namespace: default
-subjects:
-  - kind: ServiceAccount
-    name: rbd-csi-vault-token-review
-    # replace with non-default namespace name
-    namespace: default
-roleRef:
-  kind: Role
-  name: rbd-csi-vault-token-review-psp
-  apiGroup: rbac.authorization.k8s.io