add a sidekick

chart/sidekick.yaml

+apiVersion: v1
+kind: Pod
+metadata:
+  name: sidekick
+spec:
+  containers:
+    - name: sidekick
+      image: nginxinc/nginx-unprivileged:latest
+      volumeMounts:
+        - mountPath: /data
+          name: shared-data-files
+  volumes:
+    - name: shared-data-files
+      persistentVolumeClaim:
+        claimName: "release-media-files"
\ No newline at end of file