comma three: get ADB working over USB

[adeebshihadeh]

I used adb a bunch while doing the ISP debayer, and it's noticably snappier than SSH! Already works over the network using https://github.com/commaai/openpilot/blob/master/selfdrive/debug/adb.sh

Let's treat it the same as SSH:

• add a toggle to the openpilot settings UI for enabling it (default off)
• enabled if openpilot isn't installed yet https://github.com/commaai/agnos-builder/blob/master/userspace/usr/comma/comma.sh#L28

FYI, you'll need to plug into the auxiliary USB C port (bottom one) to get to the 845. The OBD-C port (main one) goes to the panda for the serial console.

[adeebshihadeh]

These are from a working Ubuntu image with adb up over usb. Not sure it's enough, but should at least point in the right direction.

adbd.txt
usb.txt

[amoghmunikote]

I think that might be enough for me to implement it.