Convert openscad renders to jpeg or webp

Images are being sent as png which is not the best web format. jpg should be much smaller, and if we can detect if they're browser supports webp that would be even better.
https://stackoverflow.com/questions/5573096/detecting-webp-support#27232658

We'll need to figure a good way of doing this in node.

There's a possibility that compressing the image then sending will take longer than just sending, but I doubt it 🤷