[etwist] pass the repository to the root resource
This is another step toward a cleaner instantiation scheme for the repo.
The http test now pass an already created object to the etwist server instead of
relying on the config cache.
Related to #2249513
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')