kraken: fix impact period vp for prefiltering
kraken: fix impact period vp for prefiltering

When impacting a stop_point the vp didn't include the last day of the impact
when the time of day of the end date was before the time of day of the start date.
Switch to date_iterator instead of time_iterator since we want to iterate on date.

patochectp/navitia,CanalTP/navitia,pbougue/navitia,kinnou02/navitia,xlqian/navitia,CanalTP/navitia,xlqian/navitia,pbougue/navitia,antoine-de/navitia,kinnou02/navitia,xlqian/navitia,patochectp/navitia,kadhikari/navitia,Tisseo/navitia,ballouche/navitia,antoine-de/navitia,ballouche/navitia,ballouche/navitia,Tisseo/navitia,Tisseo/navitia,Tisseo/navitia,patochectp/navitia,kadhikari/navitia,CanalTP/navitia,ballouche/navitia,patochectp/navitia,CanalTP/navitia,antoine-de/navitia,antoine-de/navitia,Tisseo/navitia,pbougue/navitia,kinnou02/navitia,xlqian/navitia,kinnou02/navitia,CanalTP/navitia,pbougue/navitia,kadhikari/navitia,kadhikari/navitia,xlqian/navitia