Add support for veth pair

[mnasiadka]

Currently the only supported veth is macvlan - not real veth pair like here: https://developers.redhat.com/blog/2018/10/22/introduction-to-linux-interfaces-for-virtual-networking#veth

Unless I'm mistaken of course.

[liangwen12year]

Do you try out the network_state, the veth type is supported in network_state, https://nmstate.io/examples.html#interfaces-veth.

[liangwen12year]

@mnasiadka ^^, in case that you did not see my comments.

[mnasiadka]

Thanks for tagging - missed that, will have a try tomorrow.

[liangwen12year]

Have not received any response from the reporter, thus, close this issue as the issue becomes stale.