add steps to test_checkCredentialQuestionIsNotCaseSensitive and replace name in tests to use barney instead of real name

There is no need that credential update shall do anything with person
assingments. Especially there is no need to set same categories on all
assignments.

This is the expected parameter to allow tesseract convertion.

if delivery_mode, incoterm or payment_mode is defined in Trade Model Path, we just use it and should not care one that is stored in input movement.

Use copy.deepcopy instead of asContext. Persistent object connected to zodb must not be stored in on-memory classes.

Use Base.checkConsistency to test constraints instead. This is the method which real users are using.