Support building fat Jars that package Java Modules

[jjohannes]

Problem

Currently we use the Shadow plugin which throws away all module information.

We acknowledge that building Fat Jars is useful for certain tools to have a OS/ARCH independent Jar, which is easier to handle as a jlink / jpackage image.

Solution

The idea is to package the full module Jars into a container Jar. The container Jar then contains a Launcher as entry point. Starting point.

This is now supported by: https://github.com/gradlex-org/java-module-packaging

• In a first step, we will use it directly in hiero-consensus-node: build: build 'fat module jars' instead of 'shadow jars' hiero-consensus-node#26242
• If all works well, we'll move it here as something like org.hiero.gradle.feature.fatjar and retire org.hiero.gradle.feature.shadow"