Refactor async execution handling across LDAP and Nextcloud roles

- Introduce global async configuration in group_vars/all/00_general.yml:
  - ASYNC_ENABLED (disabled in debug mode)
  - ASYNC_TIME (default 300s, omitted if async disabled)
  - ASYNC_POLL (0 for async fire-and-forget, 10 for sync mode)
- Replace hardcoded async/poll values with global vars in:
  - svc-db-openldap (03_users.yml, 04_update.yml)
  - web-app-mig (02_build_data.yml)
  - web-app-nextcloud (03_admin.yml, 04_system_config.yml, 05_plugin.yml,
    06_plugin_routines.yml, 07_plugin_enable_and_configure.yml)
- Guard changed_when and failed_when conditions to only evaluate in synchronous
  mode to avoid accessing undefined rc/stdout/stderr in async runs

  https://chatgpt.com/share/689cd8cc-7fbc-800f-bd06-a667561573bf

roles/web-app-nextcloud/tasks/05_plugin.yml

@@ -5,10 +5,10 @@
 - name: disable {{ plugin_key }} nextcloud plugin
   command: "{{ nextcloud_docker_exec_occ }} app:disable {{ plugin_key }}"
   register: disable_result
-  failed_when: >
-    (disable_result.rc | int != 0)
-    and ('No such app enabled' not in (disable_result.stdout | default('') ~ disable_result.stderr | default('')))
   changed_when: >
+    not ASYNC_ENABLED and
     ((disable_result.stdout | default('') ~ disable_result.stderr | default('')) is search('disabled'))
     and (((disable_result.stdout | default('') ~ disable_result.stderr | default('')) is not search('already disabled')))
   when: not (plugin_value.enabled | bool)
+  async: "{{ ASYNC_TIME if ASYNC_ENABLED else omit }}"
+  poll:  "{{ ASYNC_POLL if ASYNC_ENABLED else omit }}"