Implement OpenGL from window-starter

The bulk of the work to create an OpenGL context on windows and load the some of the functions required to get a triangle rendering using modern OpenGL

src/opengl.h

@@ -0,0 +1,28 @@
+#pragma once
+
+#include <memory>
+
+namespace ogl_starter
+{
+class Window;
+
+struct OpenGLCreateParams
+{
+	void* nativeWindowHandle;
+	int versionMajor;
+	int versionMinor;
+};
+
+class OpenGL
+{
+public:
+	virtual ~OpenGL() = default;
+	virtual void ClearBuffers() = 0;
+	virtual void SwapBuffers() = 0;
+
+	virtual void DrawScene() = 0;
+};
+
+} // namespace ogl_starter
+
+std::unique_ptr<ogl_starter::OpenGL> oglsCreateOpenGL(ogl_starter::OpenGLCreateParams params);