FIX: Ignore obligatory properties when inserting identifiables

Summary

See #40 (closed).

Focus

Added a flag in the insertion of identifiables in crawler.py. Also repaired the integration test for datamodel problems.

Test Environment

Integration tests should be sufficient.

Check List for the Author

Please, prepare your MR for a review. Be sure to write a summary and a focus and create gitlab comments for the reviewer. They should guide the reviewer through the changes, explain your changes and also point out open questions. For further good practices have a look at our review guidelines

• All automated tests pass
• Reference related Issues
• Up-to-date CHANGELOG.md
• Annotations in code (Gitlab comments)
  • Intent of new code
  • Problems with old code
  • Why this implementation?

Check List for the Reviewer

• I understand the intent of this MR
• All automated tests pass
• Up-to-date CHANGELOG.md
• The test environment setup works and the intended behavior is reproducible in the test environment
• In-code documentation and comments are up-to-date.
• Check: Are there spezifications? Are they satisfied?

For further good practices have a look at our review guidelines.

CHANGELOG.md

@@ -59,6 +59,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * Fixed an issue where `caosadvancedtools.cache.UpdateCache` would
   cause an `sqlite3.IntegrityError` if more than one change was cached
   for the same entity.
+* #40 Insertion of identifiables with missing obligatory properties
 
 ### Security ###