Geoclue2 agent support

Looks like current window manager does not implement Geoclue2 Agent API (https://www.freedesktop.org/software/geoclue/docs/gdbus-org.freedesktop.GeoClue2.Agent.html). An example for such implementation is at https://gitlab.gnome.org/GNOME/gnome-shell/blob/master/js/ui/status/location.js , if it is of any help. On user side, its a dialog box and settings that are kept by desktop environment to ensure that only applications with explicitly given permission have access to location data.