alpine: assume one DNS name per host

Avoid needless complexity.

roles/netbox/tasks/app.yml

@@ -49,7 +49,7 @@
     line: '{{ item.line }}'
   loop:
     - key: '^ALLOWED_HOSTS = '
-      line: "ALLOWED_HOSTS = [{{ fqdns | map('regex_replace', '^(.*)$', '\"\\1\"') | join(', ') }}]"
+      line: "ALLOWED_HOSTS = ['{{ dns_name }}']"
     - key: 'USER.*PostgreSQL username'
       line: "    'USER': '{{ user }}', # PostgreSQL username"
     # XXX unnecessary?