SW: add cloud-init to GRML_FULL

cloud-init is useful in cloud environments, also Proxmox provides support
for it.

This adds 11.5 MB of additional disk space. We consider adding it to
GRML_SMALL as well (adding 14MB there). But for the time being verify its
usefulness before adding it to grml-small as well.

Thanks Joel Wirāmu Pauling for suggesting this.

See grml/grml#124

etc/grml/fai/config/package_config/GRML_FULL

@@ -151,6 +151,7 @@ bind9-host
 bridge-utils
 cdpr
 cifs-utils
+cloud-init
 comgt
 dnsmasq
 dnsutils