feature request - ufs needs a --device parameter

[rhubarbdog]

I've got multiple microbits plugged into my laptop as I require multiple serial terminals. I plugged my micropython microbit in first so it's /dev/ttyACM0. I then plugged in a MakeCode blocks microbit. ufs defaults to the last plugged in microbit which is /dev/ttyACM1 the MakeCode one. I need to be able to specify the device I choose to microfs into

[carlosperate]

Yes, now that microfs can send and receive files to different MicroPython-based devices, it's be good to add a --port flag to indicate the port manually, so that it can be used with any MicroPython board.