Investigate removing sharding features from discord.js in favor of using @discordjs/ws sharding strategies

[didinele]

Effectively, we have to ensure you can get things working via the pattern shown in the 2nd example of this section https://github.com/discordjs/discord.js/tree/main/packages/ws#specify-worker_threads

This will require some internal changes, as right now every client spawns its own WebSocketManager. Total feature parity can totally be accomplished, we just have to think a bit about what & how we provide to users to keep sharding insanely simple. Presumably, an abstraction over the ws WorkerBootstrapper to handle all the process communication.