arch-boxes: Use qemu-headless

Signed-off-by: Florian Pritz <bluewind@xinu.at>

roles/arch-boxes/tasks/main.yml

 ---
 
 - name: install arch-boxes dependencies
-  pacman: name=packer-io,virtualbox,qemu state=present
+  pacman: name=packer-io,virtualbox,qemu-headless state=present
 
 - name: create arch-boxes user
   user: name={{ archboxes_user }} shell=/bin/bash home="{{ archboxes_home }}" createhome=yes