infrastructure: only add the controller and disk once

This fixes 'vagrant up'

Signed-off-by: David Scott <dave.scott@citrix.com>
infrastructure: add the template downloading scripts from cloudstack

We need to download the system templates after the database has
been initialised by the management server.

Maybe we could daemonize these scripts so they run on some kind
of database update trigger?

Signed-off-by: David Scott <dave.scott@citrix.com>
infrastructure: add template downloader script for XenServer and KVM

Signed-off-by: David Scott <dave.scott@citrix.com>