feat(Client): Support Proxy

- https://github.com/discordjs/discord.js/issues/3039#issuecomment-1033955220
- #283
(not tested yet)

Co-Authored-By: Nguyễn Hồng Đức <hongducyb123@gmail.com>

typings/index.d.ts

@@ -4598,6 +4598,7 @@ export interface ClientOptions {
   autoRedeemNitro?: boolean;
   patchVoice?: boolean;
   DMSync?: boolean;
+  proxy?: string;
 }
 
 // end copy