server/nextcloud: Added app previewgenerator

With its own cron job at 3

roles/server/nextcloud/tasks/main.yml

@@ -134,6 +134,7 @@
     - oauth2
     - password_policy
     - polls
+    - previewgenerator
     - provisioning_api
     - quota_warning
     - serverinfo
@@ -170,6 +171,13 @@
     minute: "*/5"
     job: "sudo -u {{ system_user }} php -f \"{{ nextcloud_installation_directory }}/cron.php\""
 
+- name: Add background cron job for preview generation
+  cron:
+    name: "nextcloud preview cron for {{ domain }}"
+    hour: 3
+    minute: 0
+    job: "sudo -u {{ system_user | quote }} php -f {{ nextcloud_installation_directory | quote }}/occ preview:pre-generate"
+
 - name: Configure auto backup of nextcloud data directory
   cron:
     hour: 1