The previous create_module actions uses section number instead of
section id. This produces several bugs when sections are moved around
the course in edit mode. This issue implements a new_module action with
all related mutations and webservices. The new one uses section id
instead of section number.
- Added unit tests for 'core_courseformat\external\create_module' web service.
- Added unit tests for 'create_module' state action.
Both tests need at least a module with 'FEATURE_QUICKCREATE', so mod_subsection
was used.