Needs new xdg-desktop-portal-gnome

- Pass --disable-silent-rules, --disable-appchooser,
--disable-background, --disable-screencast, --disable-screenshot,
--disable-settings, and --disable-wallpaper to configure, make
use of xdg-desktop-portal-gnome, and more importantly, remove all
gnome-dependencies from this package.
- Following the above, drop pkgconfig(gio-2.0),
pkgconfig(gio-unix-2.0) and pkgconfig(gnome-desktop-3.0)
BuildRequires.
- Add explicit pkgconfig(fontconfig) BuildRequires.
- Add systemd_user_post and systemd_user_preun macros to post/preun
sections.
- Update to version 1.10.0:
+ filechooser: Fix a focus issue
+ inhibit: Autostart org.gnome.ScreenSaver
+ screencast: Force window icon size
+ Make portal backends with GNOME dependencies optional and
disable them by default. Use xdg-desktop-portal-gnome, or use
--enable-wallpaper to build with the wallpaper backend
--enable-screenshot to build with the screenshot backend
--enable-screencast to build with screencast/remoting backends
--enable-background to build with the background backend
--enable-settings to build with the settings backend
--enable-appchooser to build with the appchooser backend
+ Updated translations. (forwarded request 922073 from iznogood)