[server/session] allow access to session id using sessionid
session.sessionid is a DBAPISession attribute. Having it on server side session
will helps the rework of the API to access repository. The new schema drop the
concept of DBAPISession and use server side session for the same purpose.
related to #2503918
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',)}