GeneratePMMLModelMojo has been implemented as part of https://issues.redhat.com/browse/DROOLS-5258 and it is currently present inside
https://github.com/gitgabrio/droolsjbpm-integration/tree/DROOLS-5258 branch.
Thing to fix:
currently the plugin works if the source project is correctly layed down (i.e. every pmml file in its own package and kmodule.xml manually written out).
A way is needed so that user put all pmml files inside resources/PMMLResources and the model is correctly compiled.
It is needed to have a pre-compile phase (before any compilation) where
1) resources are moved to expected "resource" subfolder
2) kmodule.xml is generated
This must happen before invocation of kie build.-

Fixed by DROOLS-5367