Have gnome-core better match what GNOME says is GNOME Core

This is a big commit so a bit difficult to explain all the changes.

The idea though is that we should be able to easily compare our gnome-core list with what is at

• https://gitlab.gnome.org/GNOME/gnome-build-meta/-/blob/master/elements/core/meta-gnome-core-shell.bst
• https://gitlab.gnome.org/GNOME/gnome-build-meta/-/blob/master/elements/core/meta-gnome-core-apps.bst

Some remaining differences from that list:

• Recommend our preferred web browsers above Epiphany. This is only a Recommends since it is common for people to use Flatpak or Snap instead (or even a different web browser)
• Have a few things as Recommends instead of Depends to make it easier for people to disable those features
  • gnome-initial-setup
  • gnome-remote-desktop (although currently gnome-control-center has a hard Depends on it because the UI is bad without it)
  • rygel Media Sharing
• Only suggested gnome-color-manager because I'm thinking it might not be needed in our default install. This does need more investigation and discussion with GNOME upstream.
• I left gnome-music in gnome because we can figure out the music player question separately but it is in GNOME Core
• I kept eog over loupe and cheese over gnome-snapshot since I think those should be decided separately too
• I did not include gnome-tour because I think it conflicts with how we use gnome-initial-setup

I believe there is a conflict between what gnome-core is supposed to be (a Debian implementation of GNOME Core) and what many people want: a minimal GNOME. I think it could be valuable if we create a separate metapackage to help those people. That can be worked on later.

cc/ @smcv