contribute osinfo metadata

[stapelberg]

We should add a distri entry to https://gitlab.com/libosinfo/osinfo-db/-/tree/master/data/os

This will allow users of gnome-boxes to easily create a distri VM :)

One wrinkle is that we must use <media> instead of <image> so that gnome-boxes shows our entry in the list of operating systems. It seems like gnome-boxes cannot create a disk from a disk image yet.