Dark Style Preference

Currently we use Electron's default mechanism for checking system settings. I like that Gnome is going to put this in DBus. That's a really good home for such information and is relatively easy to query. It might get little bit tricky in our code where we would need to step in before Electron does. I'll make an issue for this and we will see what we can do about it. I'll also see if I can get upgraded to Gnome 42, but that might not be available to me for a bit longer.