CMake libraries' config - POSTFIX

[AnastaZIuk]

TODO - use CMake to add appropriate POSTFIX according to config

Some libraries don't have adjusted postfixes to the config and it may lead to helll when using Nabla as an external project.

[devshgraphicsprogramming]

External Project or dependency via add_subdirectory ?

[AnastaZIuk]

External Project or dependency via add_subdirectory ?

Added via External Project, but it doesn't matter afaik. It is due to not set postfixes of targets correctly

[devshgraphicsprogramming]

probably a good idea to fix as part of #143