Add a quickstart example using veths (may require two-arm test?)

[chrispsommers]

The quickstart uses eth1, presumably a real NIC device. It'd be nice to have a quickstart using just veth pairs, even if it requires 2 TEs. Provide instructions including creating the veth pairs, don't make users look for the veth instructions at https://github.com/open-traffic-generator/ixia-c/blob/main/docs/prerequisites.md#network-interface-prerequisites.