[entity] add a "repo_side" parameter to `_cw_dont_cache_attribute` This parameter (defaulting to `False`) is used to inform cubicweb that we really really do not want to cache a value during creation or update. This will be used by a storage that may do very specific processing on attribute values that result in a stored value different than the provided one (e.g. BFSS `fs_importing` mode).

# -*- coding: utf-8 -*-
# copyright %(year)s %(author)s, all rights reserved.
# contact %(author-web-site)s -- mailto:%(author-email)s
#
%(long-license)s
"""%(distname)s precreate script, executed at instance creation time or when
the cube is added to an existing instance, before the schema is serialized.

This is typically to create groups referenced by the cube'schema.
"""