Update to gnome 44
- Update flatpak runtime to GNOME 44
- Update to webkit2gtk SO version 6
- Update gtk dependency to gnome 44 -- Also fix simple deprecations
- Use adw::application to remove CSS initialization -- Adwaita will automatically load style.css. So manual initialization is not needed anymore.
- Remove setting color scheme -- The default Adwaita color scheme is prefer light, so it doesn't need to be set explicitly.
cargo update