Add cmake configuration

[keiradiance]

Add CMakeLists.txt with shared library installation target.

[neov5]

tried to use this, but it worked when include_directories(src) was changed to target_include_directories(logc_shared PUBLIC src). Could not import the log.h file otherwise.

[tuaris]

I don't understand why people insist on making a shared library. The code is small and simple enough to integrate with your app. Not everything needs to be overly complex and be a shared library.