scripts,Makefile: add creation of bootable disk images

Add support for creating bootable media for use with USB or HDD boot.
Also add support for running the generated media in QEMU.

genbootimg.sh

@@ -0,0 +1,44 @@
+#!/usr/bin/bash
+
+if [ $# != 3 ]
+then
+	echo "usage: $0 size diskname"
+	exit 1
+fi
+
+if [ -z $1 ]
+then
+	echo "please pass a non empty size"
+	exit 1
+fi
+
+if [ -z $2 ]
+then
+	echo "please pass a non empty disk name"
+	exit 1
+fi
+
+if [ -z $3 ]
+then
+	echo "please pass a non empty imgdir"
+	exit 1
+fi
+
+
+# most of the below shamelessly stolen from
+# https://github.com/limine-bootloader/limine-c-template/blob/trunk/GNUmakefile
+# at commit 7310a9b098731cbd4242ed82f5c9b9c60ae14919
+
+rm -f "$2"
+truncate -s "$1" "$2"
+sgdisk "$2" -n 1:2048 -t 1:ef00
+host-pkgs/limine/usr/local/bin/limine bios-install "$2"
+mformat -i "$2@@1M"
+mmd -i "$2@@1M" ::/EFI ::/EFI/BOOT ::/boot ::/boot/limine
+
+img="$PWD/$2"
+
+cd "$3"
+#find . -type d -exec mmd -i "$img@@1M" ::{} \;
+# FIXME ^^^ breaks, but there's no dirs yet, so it doesn't matter :P
+find . -type f -exec mcopy -i "$img@@1M" {} ::{} \;