I've just dropped the Maven build scripts. It doesn't prevent from using Maven to build a project based on the engine, it only prevents from building the engine itself with Maven.
I've overridden the build-in javadoc Gradle task, it works like a charm. The tasks "publishToJogAmpMavenArdor3d" and "publishJavadocToJogAmpArdor3d" are run when I release a new snapshot in order to update the Java API documentations and to update the JARs.
N.B: I have removed the JARs from deployment/ardor3d in order to avoid duplicating the JARs of the project, I have removed the 7z archive for the same reason.
I have updated the tutorial.
The next step consists in getting rid of the deprecation warnings with Java 20.