parallels: implement VM creation

parallels: implement VM creation

To create a new VM in Parallels Clud Server we should issue
"prlctl create" command, and give path to the directory,
where VM should be created. VM's storage will be in that
directory later. So in this first version find out location
of first VM's hard disk and create VM there.

Signed-off-by: Dmitry Guryanov <dguryanov@parallels.com>