WIP: Remove TransactionError.get_errors() function

tests/test_affiliation.py

tests/test_datatype.py

tests/test_datatype_inheritance.py

tests/test_error_stuff.py

tests/test_file.py

tests/test_list.py

tests/test_misc.py

tests/test_permissions.py

tests/test_query_template.py

tests/test_tickets.py

tests/test_tickets_300.py