Kotlin for Forge

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• Updated to Kotlin 1.7.0

• Updated to Kotlin 1.6.10, coroutines 1.6.0, serialization 1.3.2
• Fix Java module issue with ObjectHolderDelegates
• Fix sources jar in gradle

• Fix generic types with registerObject to work like they used to
• Go back to using slim jars on maven (todo update the readme)
• You will now need to manually add kotlin in your build.gradle

• Updated to Kotlin 1.5.31, serialization 1.3.0
• Maven now has fat jar
• Removed KDeferredRegister and replaced with an extension function for property delegates
• Inlined a bunch of Forge.kt functions because KFF can't reference game code anymore
• Removed KotlinEventBus

• Fixed missing dependencies on Curseforge