Move functionality from evolution-alarm-notify to gnome-shell-calendar-server

As mentioned in https://bugzilla.gnome.org/show_bug.cgi?id=780076, evolution-alarm-notify's main functionality is notifications for calendar events. It would be awesome if that functionality could be moved in the shell calendar code itself, since it already knows how to send notifications (it's the notification daemon itself!) and already has access to the calendar events...