Make sure MAC randomization is used

For WiFi, MAC randomization is useful to preserve privacy in untrusted networks, to remove the tracking of your visiting hours at the local cafe or diminish the spying abilities of ISP-provided router.

The downside of this is getting assigned a different IP address every time, so this should be an option users can opt out of for networks where this matters.

This should apply to WiFi, and maybe to the USB network (because it currently connects automatically).

Side note: A similar consideration should be in effect in relation to zeroconf hostnames.