[7.0] Intentionally support Configuration on Demand

[Jonathing]

Configuration on Demand is an optimization feature in Gradle which makes it attempt to only configure the relevant projects for the requested tasks. This does not affect project import.

It is imperative to support this for multi-loader projects, as ForgeGradle is usually applied to a subproject that does not always need to be configured (i.e. running the task :fabric:jar). Configuration on demand also means that the Mavenizer invocation (discussed in #990) can be skipped if the project does not need to be configured.

So far, ForgeGradle 7 supports configuration on demand as the plugin for the applied project does not need to interact with any other projects. However, I'm creating this issue to ensure that I don't break configuration on demand by accident for any updates I make to ForgeGradle 7 until stabilization.

This issue will be closed as complete once ForgeGradle 7 is stabilized.

cc @PaintNinja @mezz