BigBlueButton & Nextcloud:

- Switch to custom BBB Docker repository
- Externalize Coturn and Collabora by default
- Add dedicated 03_dependencies.yml for dependency handling
- Improve env templating with lowercased feature flags
- Add conditional healthcheck for Greenlight
- Refactor TURN/STUN/relay handling with role variable _BBB_COTURN_ROLE
- Extend Collabora/Greenlight dependency wiring in override file
- Nextcloud Talk: refine vars and enable/disable logic with separate plugin/service flags, add network_mode support and conditional nginx proxy block

Ref: https://chatgpt.com/share/68d741ff-a544-800f-9e81-a565e0bab0eb

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

@@ -24,7 +24,7 @@ credentials: {}
 docker:
   services:
     bigbluebutton:
-      repository: "https://github.com/bigbluebutton/docker.git"
+      repository: "https://github.com/kevinveenbirkenbach/bigbluebutton-docker.git"
       version:    "bbb3.0"
     database:
       # This is set to true to pass integration test, doesn't have any other function
@@ -32,4 +32,6 @@ docker:
     greenlight:
       enabled:    true
     coturn:
-      internal:   "{{ not 'web-svc-coturn' in group_names | lower }}"
+      internal:   false
+    collabora:
+      internal:   false