Everything in the settings

[abstinent]

For a straightforward design, I would like to be able to find all settings within the Settings menu. Therefore, the "Appearance" option should be integrated there. Submenus can still be located in various places, of course.

[Anduin2017]

I tried this way before. However seems impossible without recompiling the gnome control center. I will try this in the future. That rebuilds gnome control center from scratch and add appearance settings.