Add Boxes to utilities

[cassidyjames]

It's a core GNOME app, and a useful utility if someone needs it

[castrojo]

Just to be clear, do you want it as a flatpak or on the image? I've had issues with it as a flatpak in the past but haven't investigated recently.

[cassidyjames]

I was thinking as a Flatpak in the non-default Utilities section. That's generally how GNOME recommends using it, though I know there are issues e.g. with USB passthrough. Still, it's a useful thing.