Refactor Crawler

Note, that you need an up to date scifolder to test this .

See README_SETUP.md for hints how to test this.

The mechanism surrounding "cook" was removed. The sequence during crawling ist now:

1. match a CFood with CFood.match_item
2. if True instantiate the CFood.

DoD

• integrationtests/full_test/test.sh passes
• Code reviewed and threads resolved.

Optional

• Deal with TODO in test_crawler.py: empty_identifier after https://gitlab.com/caosdb/caosdb-pylib/-/merge_requests/22