USB Booting

Write and test instructions for USB booting.

USB is probably more resilient than sd-cards. It would be good to have the knowledge of how to burn iso and boot off USB.

https://forums.raspberrypi.com/viewtopic.php?t=322604&sid=df4ec3dbf3d839908644c6940137174d&start=25#p1939516


https://github.com/raspberrypi/usbboot