Adds AsyncPlayerSendCommandsEvent
- Allows modifying on a per command basis what command data they see.
Adds CommandRegisteredEvent
- Allows manipulating the CommandNode to add more children/metadata for the client
This adds a custom pool inorder to make sure that they are closed
without much though, as it doesn't matter if the client is not sent
commands if the server is restarting. Using the default async pool caused issues to arise
due to the shutdown logic generally being much later.
