MAINT: convert the Validation exception to debug output in crawler_main

src/caoscrawler/converters.py

src/caoscrawler/crawl.py

unittests/test_data/failing_validation/cfood.yml

unittests/test_data/failing_validation/cfood2.yml

unittests/test_data/failing_validation/data.json

unittests/test_data/failing_validation/identifiables.yml

unittests/test_data/failing_validation/schema.json

unittests/test_tool.py

unittests/test_validation.py