PowerPC: Fix 'c' key booting of CD on Apple hardware

* It seems like not all NewWorld OpenFirmware
  versions support booting from CHRP scripts.
* Move Haiku elf bootloader into bootloader.b
  type tbxi. As it is in the blessed directory
  it is picked up by cd:,\\:tbxi
* Adjust bootinfo.txt to point to bootloader
  &device; ensures that the image can be started
  regardless of source media
* Adjust bootinfo.txt to use \\ as base. \\ is an
  alias for the blessed folder on the boot media
* Rename ofboot.b to ofboot.chrp to avoid confusion
* Add .txt, .html to hfs.map to identify them properly
* The haiku-boot-cd-ppc.iso now boots on my G3 PowerBook
  by holding the 'c' key at startup. The boot menu colors
  are incorrect (white background) but it is a step in
  the right direction.
* New chrp script. Blank icon for the moment, if someone
  could figure out how to make a chrp icon that would be
  neat.
* Tested working on qemu and real hardware. Need to test
  on a more modern PowerPC Mac however.