Nextcloud performance tuning and fix backup cron job

- Set loglevel=2 (warnings) and disable mail_smtpdebug via configs
- Enable opcache.enable_file_override for faster file checks
- Increase APCu shared memory from 32M to 128M
- Fix broken module.nfs_nextcloud_data reference in backup cron job
  to use the iSCSI PVC directly

stacks/nextcloud/chart_values.yaml

@@ -26,11 +26,20 @@ nextcloud:
     #   value: "true"
     # - name: loglevel
     #   value: "0"
+  configs:
+    performance.config.php: |
+      <?php
+      $CONFIG = array(
+        'loglevel' => 2,
+        'mail_smtpdebug' => false,
+      );
   phpConfigs:
     zzz-custom.ini: |
       max_execution_time = 300
       max_input_time = 300
       default_socket_timeout = 300
+      opcache.enable_file_override = 1
+      apc.shm_size = 128M
   extraVolumes:
     - name: apache-tuning
       configMap:

stacks/nextcloud/main.tf

@@ -366,7 +366,7 @@ resource "kubernetes_cron_job_v1" "nextcloud-backup" {
             volume {
               name = "nextcloud-data"
               persistent_volume_claim {
-                claim_name = module.nfs_nextcloud_data.claim_name
+                claim_name = kubernetes_persistent_volume_claim.nextcloud_data_iscsi.metadata[0].name
               }
             }