[RFE] os-net-config should add UUID to Ethernet ifcfg files

The network-init-scripts support a UUID in the ifcfg files which allows a configuration file to be associated with an interface even if the NIC name changes. The NIC name may change if persistennetnames or biosdevname settings are changed, but the UUID should match for the same hardware.

In some rare circumstances NIC names may change when upgrading the OS and changing kernel versions. By setting a UUID the ifcfg files will continue to work even if the NIC name changes.

In order to add the UUID to the ifcfg files os-net-config should call out to 'uuidgen' with the name of the interface:

$ uuidgen enp50s0
4dfc4620-c806-436f-a0a5-ad9d5ecc2e86

The UUID should be added to the ifcfg-enp50s0 file:
UUID=4dfc4620-c806-436f-a0a5-ad9d5ecc2e86

We may want to add a CLI flag which determines whether a UUID is added to ifcfg files or not.