Add recipe for native bossac flashing tool for Arduino Nano 33 BLE
There are at least two bossac variants for flashing. The one included in Zephyr does not work with the Arduino Nano board we support. Currently we suggest in the documentation to download the full Arduino IDE, strace the path to binary and set it in PATH before the user can flash.
Bossac itself is small and should be easy to build and provide as native tool. That way the -c flash_usb command will just work without any extra steps for the user.