[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)
from cubicweb.schemas.base import in_group, CWSourceSchemaConfig
# copy __permissions__ to avoid modifying a shared dictionary
in_group.__permissions__ = in_group.__permissions__.copy()
in_group.__permissions__['read'] = ('managers',)
cw_for_source = CWSourceSchemaConfig.get_relation('cw_for_source')
cw_for_source.__permissions__ = {'read': ('managers', 'users'),
'add': ('managers',),
'delete': ('managers',)}