whisper : reorganize source code + improve CMake (#2256)
* scripts : update sync [no ci]
* files : reorganize [no ci]
* sync : llama.cpp
* cmake : link math library
* cmake : build normal ggml library
* files : move headers to include
* objc : fix path to ggml-metal.h
* ci : fix WHISPER_CUDA -> GGML_CUDA
* scripts : sync LICENSE [no ci]
