Fix network monitor to use Mbps and search for available ethernet interfaces

[tabiosg]

Summary

none

What features did you add, bugs did you fix, etc?

Did you add documentation to the wiki?

never

How was this code tested?

roslaunch mrover basestation.launch

[CameronTressler]

I don't think we should have to change the yaml to work with different laptops

[CameronTressler]

You should be able to do something like this in network_monitor.py

import os iface_list = os.list_dir('/sys/class/net/')
And then check for an interface that starts with enp

[CameronTressler]

Might be slightly safer to use startswith() to check for values that start with e instead of [:1] but I don't think we could get an empty string so I don't care too much. Could be worth the extra commit if you want but I won't block on it