Feature requrest: Estimate and record trip travel times

[EwoutH]

It would be a very useful feature for me to be able to estimate and record travel times of trips in UXsim.

• [ ] Estimate the expected travel time based on the current state of the network.
• [x] Record the final travel time a trip took.

The first one can be used to make decisions on (for agents making a mode choice for example), the second can be usefull as metric / KPI.