feat: termination criterion

[sebhoerl]

This PR moves our mode share-based termination criterion to the core as a general component.

What it does:

• Smoothes the mode share signal over S=20 iterations
• Calculates the difference of the smoothed signal between the last one obtained an H=10 iterations before
• Decides to stop the simulation if the difference is less than T=0.001 for all modes

In brief: The simulation is stopped when the smoothed mode share of each mode does not change for more than 0.1%.

Output: Some useful plots that show the termination status are added.