commands: charon: reconnect to the DB

After some inactivity the mysql connection can timeout so we
need to reconnnect.
init: move airboss init script and add charon

airboss init script where in XEN roll before. Now KVM roll has his own
copy. Added also charon init script.
node.xml: remove kvm_network, from now on we only use kvm

kvm_netowrking attr is removed
kvm is the only attribute we use from now on to indicate if it is
a vm container or not