feat: export utils

[KeyboardRage]

I am using a somewhat modified version of Slash-Create to support multi-token bots. To avoid extra maintenance I simply leverage JS to modify methods, specifically, the _onRequest handler.

I bring my own slightly modified version of the method in a dedicated file and override the method and binds. However, this request handler method depends on the verifyKey utility.

It would be nice if it was also exported so I could simply import via something like this

// In my onRequest.ts
import { verifyKey } from "slash-create";

// ... rest of the _onRequest() handler, with modifications