This is the start of a new module for Paper to add support for API's
that interface Mojang API's directly.
This allows us to version properly by MC version incase Mojang makes any major breaking changes.
It also lets us separate Mojang API's from Paper-API so our downstream friends at Glowstone
will not have to worry about Mojang code.
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
