drivers: first version of the kvm_rocks allocate drivers

this script is in charge of verifing and allocating the requetsted resources
pragma_boot: now uses the new allocate driver

-removed the net_conf input arguments
-renamed numcompute into numcpus (it now allocates cpus not compute)
-adapted the script to use allocate driver
readme: updated vc-out.xml format in included allocate driver docs