tdata_delay_min needs to be limited to the active day (and/or data availablitiy)

[skinkie]

Currently the function tdata_delay_min returns the delay given tdata, that means any journey, also in the future, includes this delay. Something we should prevent.

[koch-t]

I would say this should be extended to including GTFS-RT tripupdates or at least some form of decay instead of just vehicle delay. We can/should also delete tripupdates when a delete entity arrives via websocket.