migrate target platform README / scriptlet to an actual bash script

Currently, there are three versions of this scriplet:

https://github.com/jbosstools/jbosstools-discovery/blob/master/README.building.target-platforms.adoc#updating-versions-of-ius-in-target-files
https://github.com/jbosstools/jbosstools-target-platforms/tree/master/#updating-versions-of-ius-in-target-files
https://github.com/jbosstools/jbosstools-target-platforms/tree/4.40.x/#updating-versions-of-ius-in-target-files

Instead, we should move this here:

https://github.com/jbosstools/jbosstools-build-ci/tree/master/util/verifyTarget.sh