[entity] Stop returning source information in cw_metainformation()
We should not need that. It has been introduced to handle things we should not
do and probably don't do anymore (e.g. attempting to grasp recursive import of
several sites).
Related to #15538288.
Document: cubicweb-doc
Title: CubicWeb documentation
Author: Logilab
Abstract: Some base documentation for CubicWeb users and developpers
Section: Apps/Programming
Format: HTML
Index: /usr/share/doc/cubicweb-documentation/html/index.html
Files: /usr/share/doc/cubicweb-documentation/html/*