Add RouteSubJourneys and RouteNews

- RouteNews contain information strings about each connection
between two route stops
- RouteSubJourneys contain data about routes between connecting stops
- There are now intermediate stops that are also connecting stops,
ie. intermediate stops in journeys where the vehicle gets changed
- Intermediate (not connecting) stops can be toggled in the applet
with the context menu
- Update DepartureProcessor to load sub journeys into a new
RouteSubJourney struct
- Update JourneyRouteGraphicsItem to show routes with/without
intermediate stops, but always with connecting stops
- Without RouteSubJourneys information from the engine journeys
should be drawn like before
- Add routeNews() and routeSubJourneys() to DepartureInfo
in libpublictransporthelper and add struct RouteSubJourney

TODO: Maybe turn the intermediate stop toggle action into
a StopAction to toggle specific sub journeys and not all at once
TODO: Update providers to provide such information