Get rid of ARC pathes in freeldr, ntoskrnl, hal

When installing ReactOS from a USB drive (using Vadim's yet uncommitted patches), installation runs successfully, but the freeldr.ini is written with rdisk(1) instead of rdisk(0). Consequently, booting into the newly installed system fails. It works again when freeldr.ini is fixed to use rdisk(0).

I think when USB comes into play, we cannot rely on numbering disks anymore. Therefore, we should start thinking about replacing ARC pathes in all related components (afaik freeldr, ntoskrnl, and hal). What options do we have?

• NT6 uses pathes like \Device\HarddiskVolume1. This way, it dynamically refers to the hard disk the boot loader was loaded from. I guess we want to adopt that.
• No idea how NT6 deals with partitions outside the boot loader HDD. Linux these days refers to partitions using GUIDs/volume serial numbers. We may want to adopt this as well.

Both methods would fix the problem I had with installing ReactOS from USB.