This also cleans up the implementation of Async Chunks to get rid of most
Consumer callbacks and instead return futures.
This lets us propogate errors correctly up the future chain
(barring one isn't lost even deeper in the chain...)
So exceptions can now bubble to plugins using getChunkAtAsync
This lets you run /paper fixlight <chunkRadius> (max 5) to automatically
fix all light data in the chunks.
Permission node is same "bukkit.command.paper"