Check which version of OpenGL is available, and automatically select appropriate renderer.

There's no point trying to use the OpenGL2 render if only OpenGL 1.x is available. Doing otherwise can cause crash (which always occurred when I had opengl2 painter selected and was attempting to start mythtv-setup over ssh/X)

Selecting the "Auto" painter will try to use in order: OpenGL 2.0, OpenGL 1.0 and finally Qt.
Selection "OpenGL 1" will limit the use to the OpenGL 1.x render, and disable tests such as software rasterizer detection.
There's no difference between using "Auto" and "OpenGL 2", and as such the "OpenGL 2" painter is removed from the setting.

The Qt painter will be properly selected should an error occur.

Make the OpenGL VideoOuput use the same OpenGL version as the main painter.

VAAPI with OpenGL 2.0 is still broken, resulting in a black window.