Generalized CMake VASM module

[tehKaiN]

Initial work for integrating VASM CMake module directly to CMake repo.

Related to https://gitlab.kitware.com/cmake/cmake/-/issues/25116

Everything works as intended on Bartman toolchain. I need someone to check if it's working on Bebbo toolchain too.

Steps to do:

• copy contents of Modules/m68k-amigaos-gcc to your cmake install
• inside project's CMakeLists.txt, add ASM_VASM language to project() directive
• observe if vasm-built asm sources build and link properly