[Feature] Support creating an El Torito (CD-ROM) bootable image

Hi! First off, I wanted to thank the creator and the contributors of this package for all the great work.

Now, onto the issue: I have been using the bootloader to run a small kernel I'm writing and I have noticed that while I can boot when the built image is attached as a hard drive to QEMU, I am not able to boot when it's attached as a CD-ROM. I have dug deeper and from what I've read it is because CD-ROMs have a completely separate booting system called El Torito.

As such, I would like to know if there would be a possibility of adding El Torito support and add it so we could build the images directly for booting from a CD?