use existingClaim PVCs for zulip, postgres and redis

flux2/apps/zulip/zulip-data-pvc.yaml

+---
+apiVersion: v1
+kind: PersistentVolumeClaim
+metadata:
+  name: zulip-data
+spec:
+  accessModes:
+    - ReadWriteOnce
+  volumeMode: Filesystem
+  resources:
+    requests:
+      storage: 2Gi
+  storageClassName: local-path

flux2/apps/zulip/zulip-postgres-pvc.yaml

+---
+apiVersion: v1
+kind: PersistentVolumeClaim
+metadata:
+  name: zulip-postgres
+spec:
+  accessModes:
+    - ReadWriteOnce
+  volumeMode: Filesystem
+  resources:
+    requests:
+      storage: 2Gi
+  storageClassName: local-path

flux2/apps/zulip/zulip-redis-pvc.yaml

+---
+apiVersion: v1
+kind: PersistentVolumeClaim
+metadata:
+  name: zulip-redis
+spec:
+  accessModes:
+    - ReadWriteOnce
+  volumeMode: Filesystem
+  resources:
+    requests:
+      storage: 2Gi
+  storageClassName: local-path

flux2/apps/zulip/zulip-values-configmap.yaml

@@ -41,6 +41,8 @@ data:
     redis:
       auth:
         password: "${redis_password}"
+      persistence:
+        existingClaim: zulip-redis
       resources:
         limits:
           cpu: 200m
@@ -50,6 +52,8 @@ data:
           memory: 32Mi
 
     postgresql:
+      persistence:
+        existingClaim: zulip-postgres
       postgresqlPassword: "${postgresql_password}"
       resources:
         limits:
@@ -88,6 +92,8 @@ data:
         requests:
           cpu: 400m
           memory: 1Gi
+      persistence:
+        existingClaim: zulip-data
 
     postSetup:
       scripts: