Implement lambkin-spy package

[hidmic]

Feature description

In real-world, non-monolithic systems, networking can have a significant impact in net system performance, and tracking down network issues can be daunting. LAMBKIN would benefit from a network traffic probe and easy to use APIs for parsing through that data. I think it's time for a lambkin-spy package.

Implementation considerations

tcpdump and scapy look like a good match. Even for shared memory transports in ROS 2, DDS vendors offer tcpdump compatible output.