[ENH] Adding stationary time to the Pit endpoint.

[Carol52x]

Currently the pitstop endpoint returns the full pitlane entry to pitlane exit time in seconds, along with other info, but It would be great if stationary times would've been added to this endpoint. The DHL website has an endpoint with the stationary time information but it isn't very easy to automate requests from this site due to seemingly random identifiers for different seasons. It would be great if this can be implemented from other sources which I don't know of.