Suppress warning and stdout messages in Jupyter notebooks #2420

Job	Run time
link_checker	7s
static_checks	51s
build_and_test_nest_compartmental (master)	19m 15s
build_and_test_py_standalone	1m 50s
build_and_test_nest (v2.20.2)	9m 8s
build_and_test_nest_desktop (master)	11m 12s
build_and_test_nest (v3.0)	10m 19s
build_and_test_nest (v3.8)	12m 27s
build_and_test_nest (master)	12m 33s
	1h 17m 42s

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