chg: dev: Use lists of expected artifacts in system tests
requested to merge 4261-add-pytest-fixture-checking-test-artifacts into ondrej/remove-DNSRPS-from-open-source-edition
clean.sh scripts have been replaced by lists of expected artifacts for each system test module. The list is defined using the custom pytest.mark.extra_artifacts mark, which can use both filenames and globs.
Closes #4261