Add command to get MAC address

Created by: bodzso

We need to get the mac address from the device for debugging purposes (what is really behind the IP).

• Add a command to get only the MAC address
• Update get_status text to print MAC too

commands:

https://github.com/simonyiszk/matrix4-fw/blob/47b25da92072c851b2d02d0e19f8653f3b0fc89c/Inc/network.hpp#L28-L40

status text:

https://github.com/simonyiszk/matrix4-fw/blob/47b25da92072c851b2d02d0e19f8653f3b0fc89c/Src/network.cpp#L224-L238