message: Add HTTP methods to RequestManager
diff: import Client from "../module/Client.ts";
  +import { RequestMethod } from "../types/fetch";
  +
  +type RequestBody = string | Blob | ArrayBufferView | ArrayBuffer | FormData | URLSearchParams | null | undefined;
  class RequestManager {
  client: Client;
  token: string;
  - currentRatelimit
  constructor(client: Client, token: string) {
  this.client = client
  this.token = token
  }
  - async get(url: string, payload?: unknown, shouldRatelimit = true) {
  - if (shouldRatelimit) {
  -
  + async get(url: string) {
  + const headers = this.getDiscordHeaders();
  + return fetch(url, { headers }).then(res => res.json())
  }
  +
  + async post (url: string, body: RequestBody) {
  const headers = this.getDiscordHeaders();
  - console.log('payload', payload)
  + return fetch(url, {
  + method: RequestMethod.Post,
  + headers,
  + body
  + });
  + }
  - const data = await fetch(url, { headers }).then(res => res.json())
  - return data
  + async delete (url: string, body: RequestBody) {
  + const headers = this.getDiscordHeaders();
  + return fetch(url, {
  + method: RequestMethod.Delete,
  + headers,
  + body
  + });
  }
  // The Record type here plays nice with Deno's `fetch.headers` expected type.
  