rbd: add aws-sts-metdata encryption type

With Amazon STS and kubernetes cluster is configured with
OIDC identity provider, credentials to access Amazon KMS
can be fetched using oidc-token(serviceaccount token).
Each tenant/namespace needs to create a secret with aws region,
role and CMK ARN.
Ceph-CSI will assume the given role with oidc token and access
aws KMS, with given CMK to encrypt/decrypt DEK which will stored
in the image metdata.

Refer: https://docs.aws.amazon.com/STS/latest/APIReference/welcome.html
Resolves: #2879

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

deploy/rbd/kubernetes/csi-rbdplugin-provisioner.yaml

@@ -163,6 +163,9 @@ spec:
               mountPath: /tmp/csi/keys
             - name: ceph-config
               mountPath: /etc/ceph/
+            - name: oidc-token
+              mountPath: /var/run/secrets/tokens
+              readOnly: true
         - name: csi-rbdplugin-controller
           # for stable functionality replace canary with latest release version
           image: quay.io/cephcsi/cephcsi:canary
@@ -231,3 +234,10 @@ spec:
           emptyDir: {
             medium: "Memory"
           }
+        - name: oidc-token
+          projected:
+            sources:
+              - serviceAccountToken:
+                  path: oidc-token
+                  expirationSeconds: 3600
+                  audience: ceph-csi-kms