Only ZEXP Export/Import is possible. These modules (namely OFS.XMLExportImport
and Shared.DC.xml.*) were heavily monkey-patched anyway and are only used for
BusinessTemplates.

* ERP5Type/XMLExportImport.py  => ERP5Type/XMLExportImport/__init__.py
* OFS/XMLExportImport.py       => ERP5Type/XMLExportImport/__init__.py
* Shared/DC/xml/{xyap,ppml}.py => ERP5Type/XMLExportImport/{xyap,ppml}.py