Include setup/service time in cost and add cost per setup/service

[WBNet-Wout]

Currently the setup and service time are not included in the cost. Since some workers may have a higher hourly wage than others, it may be cheaper to assign certain jobs to certain vehicles with a lower per_hour cost.

Besides, currently vehicles only support a fixed, per_hour and per_km cost. There may however be scenarios where you pay a subcontractor for example per km and per stop, or for example per stop and per parcel, which can currently not be accounted for in VROOM.

[jcoupey]

Thanks for the ticket, I also think this would be an interesting feature.

We have a related feature request (#336) for the ability to set work times that are vehicle-dependent. Those are two faces of the same coin, and probably having #336 only makes sense in the long run if we include work time in the optimization objective, as the total work time would then be varying.

In terms of implementation, the additional data we'd have to store to evaluate cost changes related to work times would probably be similar to the data needed for #336. I think we could achieve this without adding to the current algorithmic complexity.