fix(virtualization): add XML safety attributes and switch xen to virtio

roles/virtualization/tasks/libvirt.yml

@@ -23,7 +23,6 @@
   loop_control:
     label: "{{ item | to_json }}"
     extended: true
-  changed_when: false
 
 - name: Create VM disks
   delegate_to: localhost
@@ -61,6 +60,7 @@
       - "/tmp/cloud-network-config-{{ hostname }}.yml"
     creates: "{{ virtualization_libvirt_cloudinit_path }}"
 
+# uri defaults to qemu:///system (local libvirtd)
 - name: Create VM using libvirt
   delegate_to: localhost
   community.libvirt.virt: