[ENH] Adding stationary times to the pitstop endpoint.

[Carol52x]

Would be great to have stationary times in the pitstop endpoint with the data being sourced from either the DHL site or manually calculating the total time the car was stationary between PitInTime and PitOutTime from fastf1's telemetry data (although in my experiece, the latter method had inconsistencies due to the sampling rate.)

[theOehrly]

Using FastF1 telemetry for this is not accurate enough. There might be errors in the order of multiple tenths of a second there.

The DHL site might be an option. They provide exact timing and the associated lap number. It'd be a bit of work to scrape the data from there, though. But it's doable. We can keep this in mind as a potential new feature.