This commit adds the design document for adding UUID and name slots to NIC and
Disk objects and the ability to refer to them by these slots.

Signed-off-by: Christos Stavrakakis <cstavr@grnet.gr>
Signed-off-by: Dimitris Aragiorgis <dimara@grnet.gr>
Reviewed-by: Helga Velroyen <helgav@google.com>