PyOxidizer has been abandoned and will need replacing

[dae]

The tool we use to package binary builds hasn't received an update since Jan 2023, which I was nervous about. Yesterday, the project lead wrote a post admitting that they're unlikely to work again on it in the future. It's possible someone else will pick it up, but it was a complex project, so I suspect nobody will. It's a shame, because it's considerably nicer than the PyInstaller packaging tool we were using previously.

There's no immediate rush to switch away from PyOxidizer, but we will eventually need to, either when we want to upgrade past Python 3.9/10, or when PyOxidizer sufficiently bit-rots.