host_vars/aur-dev: Add host_vars for aur-dev.archlinux.org

Added a host_vars entry for aur-dev.archlinux.org.

host_vars/aur-dev.archlinux.org

+---
+filesystem: btrfs
+zabbix_agent_templates:
+  - Template OS Linux
+  - Template App Borg Backup
+  - Template App HTTP Service
+  - Template App HTTPS Service
+  - Template App MySQL
+  - Template App Nginx
+
+mysql_backup_dir: "/root/backup-mysql"
+mysql_backup_defaults: "/root/.backup-my.cnf"
+
+fail2ban_jails:
+  sshd: true
+  postfix: false
+  dovecot: false
+  nginx: false