Add network interface MAC addresses in System Info

[damajor]

Issue description

Hello,

Connecting the first time on secure Wifi networks that filter client with MAC address can be a pain if the UI does not show this information.

So adding MAC addresses for all network cards in "System Setting" -> "Information" could be a real good idea I think.

Cheers :)

[fabricecaruso]

I'm closing this issue because it's not related to EmulationStation.
The system information is provided by a script in batocera-linux.