Refactor Maven plugin to adopt best practices

by following the manual https://books.sonatype.com/mvnref-book/pdf/mvnref-pdf.pdf
Sect.11.4+

Our plugin uses non-namespaced, stringly-typed properties to be configured:

-DgenerateModel=YES

while most plugin use typed namespaced, dot-cased properties, e.g.:

-Dkie.generate.model[=true]

investigate proper conventions by reading the manual and implement the solution

*deliverable* a PR