[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.