[cmake] replace cpp glob with script and cmake include

[grf14003]

Currently, we use a file(GLOB_RECUSE...) #8 call to collect a list of source files for compilation. As stated in the CMake documentation, this is bad practice.

https://cmake.org/cmake/help/v3.14/command/file.html#glob

Instead, we should have an independent script for generating this list of source files. Some sort of process similar to this StackOverflow solution:

https://stackoverflow.com/questions/45090926/cmake-generate-list-of-source-files-without-glob