Add opengl images

[spuder]

I'm attempting to troubleshoot a problem where openscad crashes but only when running in docker. It seems to be related to opengl.

To troubleshoot, I built images based on nvidia/opengl docker container.

While the bug is still present in the nvidia/opengl so these containers weren't necessary, I'm sharing this dockerfile in case it is useful to anyone else.

• https://techsparx.com/software-development/docker/display-x11-apps.html
• https://medium.com/@benjamin.botto/opengl-and-cuda-applications-in-docker-af0eece000f1

[t-paul]

As the images don't help with the issue, I tend to think it's better sharing those separately. Increasing the list of things to maintain in the official repository does not scale well if it's just me.

[spuder]

Agreed. Thy are public now in this PR so someone can find them later if needed.