Add AGE java driver to Maven Central

**Is your feature request related to a problem? Please describe.**
Currently, we have to clone and compile [java driver](https://github.com/apache/age/tree/master/drivers/jdbc) manually if we want to get AGType in JVM project (including Scala/Clojure projects as well).

**Describe the solution you'd like**
Ideally, we'd get this using Maven versions/coordinates, tied to particular AGE version. Then, it can be fetched via maven/gradle/leiningen/sbt automatically.

Any chance we get this one soon? My assumption is that adjusting release scripts to automatically build & push java driver to Maven Central should not be that hard, but I might be wrong :)