[core] add support for bare ReactOS boot record installation

* A new "ReactOS" is now available under "Create a bootable disk" when running in advanced mode.
* Using this option will install the ReactOS bootblocks (MBR & FAT PBR) _only_.
  You can then copy freeldr.sys and freeldr.ini to make the drive bootable.
* Also move Rufus MBR installation to ms-sys, and remove mbr.bin resource.
* Also add Rufus MBR detection, remove duplicate records and display MBR type on drive detection
* Also move PBR and MBR analysis calls to drive.c and add a drive.h header
* Also make extraction of embedded loc file more robust