The usboot repo comes with a bunch of different gadgets
which can be used to boot Raspberry Pis via a USB boot cable.
Until now, we have only included the `msd` (Mass-storage device).
However, this gadget is deprecated and has since been replaced by
the `mass-storage-gadget`. Furthermore, there are now more gadgets
like the one for configuring secure boot or update/recover RPi4/5
boot eeprom.
This change installs the new gadgets under $out/usr/share/rpiboot.
