Add XfceConsolekit and XfceSystemd
It's about sharing code used by xfce4-session and xfce4-power-manager, like XfceScreensaver in libxfce4ui!89 (merged). There were more differences between the two sources this time though. Xfce4-session was preferred, both because the API was more extensive and because the implementation was better.
Related: libxfce4ui!89 (merged)