LPS-33626

Hey Julio,

this is a small but important change to make a step forward to change the current way how we handle the portlet-data.xml. Mate removed the data string from the data handlers API method signatures and generated the document with its root element before the doExportData /doImportData calls and put it into the data context. From now the export/import implementations are using the data context to fetch the xml elements.

cc'-ing: @matethurzo

thanks,
Daniel