Create the gpu library

Put the "gpu" folder that we started building in interface in its own library

Currently the gpu library also link to openGL and Glew (on windows) and #include the gl headers public.
So anything including any file from gpu should have the gl headers too right now.
This will change when we will remove any public usage of GL which is the goal down the line.

The windows version also links the NSIGHT library when present in order to instrument the code using the nsight tools. this could be part of a different library but since the rendering is so critical performance wise, there it is so we can use the NSIGHT markers.

For the linux version we probably need Andrzej to make sure it's compiling as expected. thanks!