clean up project root #1748

Job	Run time
ubuntu (ubuntu-latest, 3.10, tests/model)	11m 15s
windows (windows-latest, 3.12, tests/model)	18m 21s
ubuntu (ubuntu-latest, 3.10, tests/statespace/test_statespace.py)	9m 10s
windows (windows-latest, 3.12, tests/statespace/test_statespace.py)	15m 48s
ubuntu (ubuntu-latest, 3.10, tests/statespace/test_kalman_filter.py)	3m 33s
windows (windows-latest, 3.12, tests/statespace/test_kalman_filter.py)	7m 29s
ubuntu (ubuntu-latest, 3.10, tests/statespace --ignore tests/statespace/test_statespace.py --igno...	8m 35s
windows (windows-latest, 3.12, tests/statespace --ignore tests/statespace/test_statespace.py --ig...	14m 9s
ubuntu (ubuntu-latest, 3.10, tests/distributions)	8m 6s
windows (windows-latest, 3.12, tests/distributions)	14m 30s
ubuntu (ubuntu-latest, 3.10, tests --ignore tests/model --ignore tests/statespace --ignore tests/...	15m 2s
windows (windows-latest, 3.12, tests --ignore tests/model --ignore tests/statespace --ignore test...	25m 55s
all_tests	1s
	2h 31m 54s

Provide feedback