Define a final list of flatpaks

[castrojo]

Right now we just snag the complete list from bluefin. We should consider just using anything in the org.gnome namespaces as a package if possible, and consider dropping it if not.

The Fedora Media Writer pulls in the entire kde runtime so I think we should drop it for the ISO, people can post-install. That leaves:

io.github.dvlv.boxbuddyrs - I'm unsure if bringing this here makes sense, it might be worth just leaving it out and encouraging people to use containers as intended since this is an LTS audience.
com.github.rafostar.Clapper - currently behind on gnome runtimes but I'm monitoring the situation, worse case we use celluloid.

Must have:
io.missioncenter.MissionCenter
org.mozilla.firefox
org.mozilla.Thunderbird
com.mattjakeman.ExtensionManager
com.github.tchx84.Flatseal
io.github.flattool.Warehouse

[p5]

Do we want to replace MissionCenter with Resources, since it's a gnome-circle app, and therefore may be better supported upstream?

On first glance, I can see Resources seems to have more frequent commits, though MissionCenter has more contributors.

https://apps.gnome.org/en-GB/Resources/

[castrojo]

MC has served us well, both apps are fantastic and well maintained, I don't think it's worth switching -- the flatpaks are trivial to swap out so I don't think we need to make a strong decision here, I'm more in the "just leave it" camp.

The service management in MC is also pretty useful.