Use standard modules HTTP server

[satyarohith]

We currently use addEventListener("fetch", ...) to handle requests and it requires deployctl. And Sift apps can't be run using Deno CLI. We can move to use the server from standard modules which is supported on Deno Deploy. This will enable us to support both Deno and Deploy.

Example usage of the API from docs:

import { listenAndServe } from "https://deno.land/std@0.110.0/http/server.ts";

listenAndServe(":8000", () => new Response("Hello World\n"));

console.log("http://localhost:8000/");

[satyarohith]

Closed by #41