CarAverageSpeedParser should use estimated max speed

[otbutz]

The MaxSpeedCalculator is currently called in GraphHopper.postImport() to fill in the missing max_speed values. This is too late for the values to be picked up by the CarAverageSpeedParser.

[Peter]

It is not possible because we need urban_density for max_speed and urban_density is only available once we have all the road network. But you can use a custom model to limit the car speed to max_speed.