feat: customizable distance calculators for drt constraints

[sebhoerl]

This PR makes it easy to further experiment with the distance objective and range constraint that comes with drt-extensions/insertion. It is now possible to flexibly configure the distance calculator with a custom logic. Furthermore, the distance approximator can be defined. While the calculator is used in the distance objective, both of them are used in the range constraint: If an approximator is defined (but it is optional), the range constraint is first evaluated with the approximator, which should be pessimistic. Only if a violation of the constraint is detected using this pessmistic (i.e. overestimating) setting, the more exact calculator is used that will perform a direct network routing by default. Both elements can now be configured by:

DrtInsertionModule insertionModule = new DrtInsertionModule(drtConfig) //
  .withVehicleRange(100.0 * 1e3) //
  .withDistanceCalculator(distanceCalculator) //
  .withDistanceApproximator(distanceApproximator);

The values passed can either be an instance of DistanceCalculator and DistanceApproximator, or they can be a class name, then a modal binding needs to be provided somewhere (see example in the unit tests).