Cleanup cross-project dependencies

[Technici4n]

• Use attributes to resolve the correct variant of the neoforge project, in tests. Since runtimeElements and universalJar have the same attributes, and adding attributes to universalJar would be a breaking change, I added an internal attribute to runtimeElements instead.
• Fix testframework being published with a runtime dependency on the universal jar. Now there is no dependency whatsoever.
• Fix java version attribute of the universalJar being the Java version used to run Gradle rather than the Java version of the toolchain.

[neoforged-pr-publishing]

• Publish PR to GitHub Packages

Last commit published: 169fb5ab69ac55028efd7a000f1b076597f2ccde.

PR Publishing

The artifacts published by this PR:

• 📦 net.neoforged:neoforge:21.4.82-beta-pr-1923-cleanup-x-project-deps
• 📦 net.neoforged:testframework:21.4.82-beta-pr-1923-cleanup-x-project-deps

Repository Declaration

In order to use the artifacts published by the PR, add the following repository to your buildscript:

repositories {
    maven {
        name 'Maven for PR #1923' // https://github.com/neoforged/NeoForge/pull/1923
        url 'https://prmaven.neoforged.net/NeoForge/pr1923'
        content {
            includeModule('net.neoforged', 'neoforge')
            includeModule('net.neoforged', 'testframework')
        }
    }
}

MDK installation

In order to setup a MDK using the latest PR version, run the following commands in a terminal.
The script works on both *nix and Windows as long as you have the JDK bin folder on the path.
The script will clone the MDK in a folder named NeoForge-pr1923.
On Powershell you will need to remove the -L flag from the curl invocation.

mkdir NeoForge-pr1923
cd NeoForge-pr1923
curl -L https://prmaven.neoforged.net/NeoForge/pr1923/net/neoforged/neoforge/21.4.82-beta-pr-1923-cleanup-x-project-deps/mdk-pr1923.zip -o mdk.zip
jar xf mdk.zip
rm mdk.zip || del mdk.zip

To test a production environment, you can download the installer from here.

[neoforged-releases]

🚀 This PR has been released as NeoForge version 21.4.78-beta.