Refactor TURN/STUN handling:

- Split internal/external Coturn for BBB and Nextcloud
- Added dedicated relay port ranges per app
- Updated env and compose overrides for coturn
- Ensure coturn role is loaded conditionally
- Standardize credential/env passing for coturn
@See https://chatgpt.com/share/68d6f376-4878-800f-b4f7-62822caa49ea

roles/web-app-bigbluebutton/tasks/main.yml

@@ -68,3 +68,13 @@
   include_tasks: "02_administrator.yml"
 
 
+- name: "Load Coturn Role for '{{ application_id }}'"
+  include_role:
+    name: web-svc-coturn
+  vars:
+    flush_handlers: true
+  when:    
+    - run_once_web_svc_coturn is not defined
+    - not BBB_INTERNAL_COTURN_ENABLED
+
+