platform: support quad-NIC servers on Packet (n2)

[vielmetti]

Feature Request

Environment

What hardware/cloud provider/hypervisor is being used to run Afterburn?

Packet, specifically the n2 servers

Desired Feature

At

afterburn/src/providers/packet/mod.rs

Line 248 in d56ad64

// According to the folks from packet, all the addresses given to us in the

the Packet provider properly handles dual-NIC systems, but does not currently support the quad-NIC n2 system type.

Other Information

Noted by Kinvolk in the course of an integration.

[vielmetti]

Also noted is packethost/packngo#173 where some of the relevant data is being returned wrong - it's possible that this issue in packngo and the Packet API will, when fixed, make this issue go away.