evaluation: add tools to create statistics for simulation runs

src/evaluation/statistics.py

src/test/evaluation/statistics/__init__.py

src/test/evaluation/statistics/compute_statistics.py

src/test/evaluation/statistics/count_or_zero.py

src/test/evaluation/statistics/max_or_zero.py

src/test/evaluation/statistics/mean_or_zero.py

src/test/evaluation/statistics/std_or_zero.py