vmm/virtualbox: Genericize setup configuration file
vmm/virtualbox: Genericize setup configuration file

- Rename virtualbox.setup to parcel.setup so that, in principle, it could
be used by more than one VMM

- Rename "show-firstrun" property to "preconfigured" and invert its sense

cmusatyalab/openisr,cmusatyalab/openisr,cmusatyalab/openisr,cmusatyalab/openisr,cmusatyalab/openisr