Generate package-info files for all impl and mixin packages (#2615)

* Generate package-info files for all impl and mixin packages

* Add javadoc to generated package-infos, use multiline string

* Simplify code

* Remove manual ApiStatus.Internal on impl classes

* Update CONTRIBUTING.md to remove ApiStatus.Internal for impl classes

* Fix Gradle deprecations

* Fix more Gradle deprecations

* Add task metadata

* Support client-main split

* Remove workaround for client packages

* Try to fix Gradle 8 deprecations

* Try to fix Gradle 8 deprecations, part 2

I'm hoping that using the SourceDirectorySet instead of converting it to a
Set<File> (which is pointless?) will carry the build dependencies over.

* Add clean packageInfo task

Co-authored-by: modmuss50 <modmuss50@gmail.com>

(cherry picked from commit 0d0f21023d)

fabric-transfer-api-v1/src/main/java/net/fabricmc/fabric/impl/transfer/item/SpecialLogicInventory.java

@@ -16,14 +16,11 @@
 
 package net.fabricmc.fabric.impl.transfer.item;
 
-import org.jetbrains.annotations.ApiStatus;
-
 import net.minecraft.item.ItemStack;
 
 /**
  * Internal class that allows inventory instances to defer special logic until {@link InventorySlotWrapper#onFinalCommit()} is called.
  */
-@ApiStatus.Internal
 public interface SpecialLogicInventory {
 	/**
 	 * Decide whether special logic should now be suppressed. If true, must remain suppressed until the next call.