Via search fixes

[pablohoch]

Fixes the following bugs in the via search implementation that caused reconstruction errors:

• If a trip passing a via stop has in/out allowed = false at the via stop, reconstructing the journey failed.
• Queries where the last via stop is also a destination and has a non-zero stay duration were not handled properly. They are now handled as follows:
  • Intermodal destination (probably the only useful case): Stay duration at the last stop is added as waiting time between the arrival + start of the intermodal footpath. Transfer time at the last stop is ignored.
  • Station destination: Stay duration at the last stop is ignored (i.e. same result as if stay = 0 in the query). The stay duration can't be properly represented in the output journey in this case, but this doesn't seem like a useful case anyway.

[felixguendling]

🎉