programs: Deprecate gvfs utils in favour of new gio tool

New gio cmd tool has been added in GLib. The tool collects and unifies
the various gvfs- utils. The gvfs- utils use GIO APIs anyway, so it
makes sense for them to be part of GLib and doesn't longer make sense to
maintain them here. Let's remove them and add scripts spawning new gio
tool with deprecation warning instead.

https://bugzilla.gnome.org/show_bug.cgi?id=769378