add basic usb install support (see commit message).

transfers seems to work, although i have done very little testing.
i plan to extend the usb script so that it supports normal usb transfers, such as uploading and
downloading files to and from the switch.

however, most users are likely better off using mtp for said transfers.

the usb transfer code was taken from Haze, which is part of Atmosphere.

.gitignore

@@ -22,3 +22,5 @@ libs/tweeny
 
 compile_commands.json
 out
+
+usb_test/