feat(tools, base): Add support to generate PBOOT.PBP and to sign VITA PSPemu PBOOT.PBP

[GrayJack]

• PrxEncrypter updated to support signing VITA PSPemu PBOOT.PBP
• mksfoexupdated with argument to generate PBOOT.PBP
• Add support for ENCRYPT=2 in build.mak
• Add support for ENCRYPT in build_prx.mak
• Add support to generate PBOOT.PBP and sign VITA PSPemu PBOOT.PBP on CMAKE create_pbp_file

[JoseAaronLopezGarcia]

These changes are very important, specially to preserve the ability to generate Vita OFW compatible PSP Homebrew and also forms the basis for ARK's loader on PS Vita.

I have personally tested and confirmed the changes work for generating signed/encrypted PBOOT.PBP that the PS Vita accepts as valid and do not break any previous builds such as PSP OFW encrypted binaries.

[GrayJack]

This last commit is a fix I did locally so many months ago, and now that I did a new environment, I got it again

CMake Error at .CMakeLists.txt:3 (project):
  The CMAKE_C_COMPILER:

    psp-gcc

  is not a full path and was not found in the PATH.

  Tell CMake where to find the compiler by setting either the environment
  variable "CC" or the CMake cache entry CMAKE_C_COMPILER to the full path to
  the compiler, or to the compiler name if it is in the PATH.

Passing a full path solves the issue and don't break when the binaries are in the path

The change is small enough that I decided to add in this PR

[sharkwouter]

This looks fine, but I'll still need some time to test this. I did have one small comment.