feat(web-app-drupal): add Drupal role, OIDC config, and wiring

- networks: add web-app-drupal subnet 192.168.104.80/28
- ports: map localhost http port 8060
- add role files: tasks, vars, schema, users, templates (Dockerfile, docker-compose, settings.local.php, upload.ini)
- add docs: README.md and Administration.md

Ref: https://chatgpt.com/share/690535c5-b55c-800f-8556-5335a6b8a33f

roles/web-app-drupal/templates/env.j2

@@ -0,0 +1,7 @@
+DRUPAL_DB_HOST=      "{{ database_host }}:{{ database_port }}"
+DRUPAL_DB_USER=      "{{ database_username }}"
+DRUPAL_DB_PASSWORD=  "{{ database_password }}"
+DRUPAL_DB_NAME=      "{{ database_name }}"
+
+# Debug flags (optional)
+DRUPAL_DEBUG={{ MODE_DEBUG | lower }}