[datafeed] Add a raise_on_error parameter to DataFeedSource.extid2entity
And pass the option from various `process_` methods in existing parsers.
This makes debugging in tests easier.
Closes #4601191.
change_attribute_type('CWCache', 'timestamp', 'TZDatetime')
change_attribute_type('CWUser', 'last_login_time', 'TZDatetime')
change_attribute_type('CWSource', 'latest_retrieval', 'TZDatetime')
drop_attribute('CWSource', 'synchronizing')
add_attribute('CWSource', 'in_synchronization')