Expose Flatpak's end-of-life information

[TingPing]

A commit in flatpak can be marked end-of-life, as in it is no longer expected to get updates, and with that it can have a custom message or redirect to a new package replacing it. Appcenter should expose this information in the UI in some form.

The basic API docs are here:

• http://flatpak.github.io/flatpak/reference/html/FlatpakTransaction.html#FlatpakTransaction-end-of-lifed

• http://flatpak.github.io/flatpak/reference/html/FlatpakRemoteRef.html#FlatpakRemoteRef--end-of-life

[danirabbit]

Design wise I think probably some kind of floating infobar (like we use in mail) or some other kind of warning banner placed very prominently on the page would work

[isantop]

It might also be a good idea to hide search results of EOL packages on systems that don't have that package installed, or at least if they provide an alternative package instead. Would help reduce the usage of unmaintained software.

[cassidyjames]

I just realized it's weird that this is not in the AppStream data for a release instead. 🤔 That seems like it would be an appropriate place to store and retrieve that information.