Even if subContent concept is no longer used, there is still code related to it in the createContentFunction.

PARENT_CONTENT_ID_KEY and PARENT_CONTENT_METADATA_PATH_KEY should be removed, the property "ametys-internal:subContent" sould no longer be set, and the _getSubContentRoot function should be removed. 

The ContentWorkflowHelper should also be modified : 

_getCommonInputsForCreation should no longer put PARENT_CONTENT_ID_KEY and PARENT_CONTENT_METADATA_PATH_KEY values, and createContent functions should no longer take parentContentId and parentContentMetadatapath as parameters.

Two createContent functions should be removed, and each call to the modified/deleted createContent functions should be modified.