Analyzing car traffic and transport costs for any given simulation iteration

[FlxPo]

For now all evaluation methods of the model's results are applicable to the last simulation iteration. We cannot analyze car traffic or transport costs for a given iteration, to see how they evolve during the simulation. It would be helpful both to debug and to be able to analyze results step by step, which is now important if behavioral parameters change during the simulation (#283).

To do this we have to store the necessary artifacts on disk at each step of the simulation, and be able to read it back when needed. We can leverage the Asset class to handle the creation of the artifacts, but we would need to add a layer of logic to handle iterations.