Manage the plexus-utils dependency in full WildFly's own dependencyManagement

Various testsuite modules in WildFly and WildFly Core use org.codehaus.plexus:plexus-utils. Full WildFly is relying on the imported dependencyManagement from WildFly Core to control the version. But core shouldn't be exposing test-only dependencies; those should be managed via its testbom model. So have full WF manage this itself.

As part of this consider bumping the version which is far behind the current.