Revert "Remove NM connectivity check file from al.org"

This is causing issues for a small business, which can't reach their "remote systems" anymore due to NM reporting "limited access". We should be able to revert this in 1-2 weeks.

This reverts commit b909fa58.

roles/archweb/defaults/main.yml

@@ -10,6 +10,7 @@ archweb_domains_redirects:
         'planet.archlinux.org': '/planet$request_uri'
 archweb_domains_templates:
         'ipxe.archlinux.org': 'ipxe.archlinux.org.j2'
+archweb_network_check_domain: 'www.archlinux.org'
 archweb_allowed_hosts: ["{{ archweb_domain }}", 'ipxe.archlinux.org']
 archweb_nginx_conf: '/etc/nginx/nginx.d/archweb.conf'
 archweb_repository: 'https://github.com/archlinux/archweb.git'