recommended-downloads: Does not show new release quickly enough
Issue
When Ubuntu 23.10 is released on October 12, I want GNOME Boxes in Ubuntu 23.04 to show Ubuntu 23.10 as a recommended download but not before that date.
We prevent Ubuntu 23.10 from showing before that date by setting its osinfo-db entry to release-status: prerelease
Ubuntu does have a Stable Release Update (SRU) process but SRUs need to be prepared more than a week in advance. This is possible if we're organized. Once an SRU is released as an update, Ubuntu uses a phased update mechanism to slowly make the update available to users. It takes 2.5 days for an update to be fully phased (it is possible to ask for a manual exception to this). Even then, non-security updates are only shown by the Update Manager tool to Ubuntu users once per week by default.
Suggested Fix 1
Use the release-date field (when present) instead of release-status to determine whether GNOME Boxes shows an OS as available for download.
I looked through the osinfo-db files as of the 20230518 tag and none use both pre-release and a release-date.
This would require gnome-boxes (or libosinfo?) to parse the release-date and compare it to the current date. If this is done, we would no longer set pre-release for an OS like Ubuntu 23.10 where the future release date is reasonably known.
Suggested Fix 2
Allow the release-status field to be overriden by recommended-downloads.xml
This assumes that distros can update the online version of recommended-downloads much quicker than using their SRU process and that the offline use case is not very important.