zope4: XML Export/Import feature was removed from Zope4.
@nexedi This is part of the work done on zope4py3 that I'm starting to merge to master. With Zope4, 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
All Unit Tests pass.