Document mysql-data-encrypted PVC as pre-existing, unmanaged resource

The mysql-data-encrypted PVC exists in the cluster and is working correctly,
but attempting to manage it through Argo CD causes sync failures because the
PVC is already bound and its spec is immutable. Leaving it unmanaged while
documenting its existence.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

apps/bookstack/bookstack-deployment.yaml

@@ -62,20 +62,7 @@ spec:
         persistentVolumeClaim:
           claimName: mysql-data-encrypted
 ---
-# MySQL Data PersistentVolumeClaim
+# Note: mysql-data-encrypted PVC is pre-existing and not managed by Argo CD
-apiVersion: v1
-kind: PersistentVolumeClaim
-metadata:
-  name: mysql-data-encrypted
-  namespace: bookstack
-spec:
-  accessModes:
-    - ReadWriteOnce
-  storageClassName: hcloud-volumes-encrypted
-  resources:
-    requests:
-      storage: 20Gi
----
 # MySQL Service
 apiVersion: v1
 kind: Service