Reorganize source files into logical subdirectories

Co-authored-by: Hirek193 <23196899+Hirek193@users.noreply.github.com>

rendering/openglmatrixstack.cpp

@@ -0,0 +1,12 @@
+/*
+This Source Code Form is subject to the
+terms of the Mozilla Public License, v.
+2.0. If a copy of the MPL was not
+distributed with this file, You can
+obtain one at
+http://mozilla.org/MPL/2.0/.
+*/
+
+#include "stdafx.h"
+
+opengl_matrices OpenGLMatrices;