Loading Spinner

[merowin]

It would be nice to have a loading spinner (e.g. displayed while the games list is being loaded), and we could create a go variants themed one! Here's a design idea:

On the technical side, I have no idea yet how this would work. I'm thinking we should probably add it as an asset, so it can be rendered as quickly as possible. But then it would not adapt to light / dark mode (as opposed to animating it with svg or such).