Add simple BRSP generator

[RobertBuhren]

The emulator is useless without either the on-chip BL or a boot-rom-service-page for the UEFI image used. Maybe we should add support to the emulator for generating a basic BRSP for a given UEFI file.

[AlexanderEichner]

The requirement for this is to have some basic flash file system parsing functionality in the emulator to extract the AMD public key from the UEFI image.

[AlexanderEichner]

Basic support for this is now available in master. There are still a lot of gaps but the most essential stuff is generated and filled in now.