[entities] Move CWSource update_config method as a function in 3.15 migration script
This script is the only caller of this method. In the code of the function,
drop "skip_unknown" argument and continue accordingly upon OptionError.
Data model
==========
This chapter describes how you define a schema and how to make it evolves as the time goes.
.. toctree::
:maxdepth: 1
definition
metadata
baseschema
define-workflows