Upgrade jaxb2-maven-plugin from 1.5 to 2.2

We are seeing intermittent build failures related to jaxb2-maven-plugin in droolsjbpm-integration repo (kie-remote-jaxb-gen module). Upgrading to latest 2.x version should fix these issues. We should also upgrade to latest version because we are at a start of the development cycle and the risks of breaking something are more acceptable.