[test] drop dependency on third party cubes
Drop dependency on cubicweb-file, cubicweb-localperms, cubicweb-tag and
cubicweb-comment for cubicweb.test and cubicweb.sobjects.test
Move cubicweb/test/data/libpython/cubicweb_* to cubicweb/test/data, so it's
included in PYTHONPATH.
Add missing parts of schema, entities, views, hooks that make tests pass.
for table, column in [
('transactions', 'tx_time'),
('tx_entity_actions', 'tx_uuid'),
('tx_relation_actions', 'tx_uuid')]:
repo.system_source.create_index(session, table, column)
commit()