Finish the ant-to-maven build migration

There are still some ant tasks that haven't yet been migrated to the Maven build, in particular the `ant create-tck-audit-file`.
Let's review the https://github.com/jakartaee/validation-spec/blob/main/build.xml and migrate the build entirely to Maven.
If there are no out-of-the-box plugins to replicate the not yet migrated ant tasks, we can explore the option of running a Groovy script (GMavenPlus), exec plugin or as a last resort, the maven-ant plugin.

Start by reviewing build.xml, especially the ant create-tck-audit-file task, and compare the remaining Ant tasks with the existing Maven build. Identify how each task could be handled with a plugin, GMavenPlus, the exec plugin, or maven-ant. Done means the build is fully migrated to Maven and the remaining Ant tasks are replicated.

Written by the indexing model from the issue text.