[entity] upgrade fetch_[unrelated_]order to benefit from changes introduced in 3.14 (closes #1942758) of rql generation parts of the ORM now based on rql syntax tree. This allows more powerful and flexible sort control by giving them the syntax tree instead of manipulating string. Also: * prefix new methods by 'cw_' * fix cases that currently crash in 3.14 due to the refactoring

# 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.
"""