My goal is to create a simple script that could be embedded in any page and which would then render any linked glb files automagically.
If it's useful, I'll add configurability and more behavior (e.g. allow the user to pan and zoom, play animations, etc.)
Usage: assuming you have the glb-viewer directory installed somewhere on a site,
you should be able to insert <script src="path/to/glb-viewer.js"></script>
at the bottom of your page and voila!