RSL: Various Improvements

[pablohoch]

• API:
  • Add new active time filter option for trip + group filter APIs (trip/group must be active/en route in the given time window)
  • /paxforecast/apply_measures: Return an error if rt updates can't be parsed (partially applied measures won't be rolled back)
• Web UI:
  • Date filter is now optional for trips + groups
  • The new active time filter is used if a date is selected
• Config:
  • New option to split journeys with long wait times at a station into separate groups: paxmon.max_station_wait_time