LPS-41187 Extract logic to getNewArticle method
LPS-41187 Use ddmStructureId param
LPS-41187 Use Validator instead of null check
LPS-41187 Revert "LPS-41187 Extract logic to getNewArticle method" & "LPS-41187 Use ddmStructureId param"
LPS-41187 Set value for input 'structureId' after selecting a new structure in the Structure Selector

When a user chooses a DDMS in  /dynamic_data_mapping/select_structure.jsp, the input data will contain both ddmstructureid & ddmstructurekey.

We use the latter one in the /journal/add_button.jsp to render the "add" option for each structure.

This commit applies the existing pattern.
LPS-41187 Avoid duplicate input fields for 'structureId'

Without this modification, that JS code below

document.<portlet:namespace />fm1.<portlet:namespace />structureId.value = event.ddmstructurekey;

could not be executed, as there would be two input fields in the form for 'structureId'.