Extend vdsm-tool: moving configure libvirt to external shell script

Using vdsm-tool to configure libvirt

Change-Id: Id58b129afbf141a47a85b421961bf5b1776b41e4
Signed-off-by: Yaniv Bronhaim <ybronhei@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/15216
Reviewed-by: Federico Simoncelli <fsimonce@redhat.com>
Reviewed-by: Dan Kenigsberg <danken@redhat.com>