[entity] add an official ``cw_etype`` property for entity This property holds the CWEtype id of the entity. This information was previously available through __regid__ but this is an ugly public API. So we have a new clean public API. The ``dc_type()`` method could not be used as it is translated. (closes #2793792)

.. -*- coding: utf-8 -*-


Server Architecture
-------------------

.. image:: images/server-class-diagram.png

`Diagramme ArgoUML`_

[FIXME]
Make a downloadable source of zargo file.

.. _`Diagramme ArgoUML`: cubicweb.zargo