rewrite endpoints for consistancy and modularity (#1323)

* rewrite endpoints for consistancy and modularity

* clean up a bit

* add missing endpoint

src/util/Util.js

@@ -1,5 +1,5 @@
 const superagent = require('superagent');
-const botGateway = require('./Constants').Endpoints.botGateway;
+const Constants = require('./Constants');
 
 /**
  * Contains various general-purpose utility methods. These functions are also available on the base `Discord` object.
@@ -54,7 +54,7 @@ class Util {
   static fetchRecommendedShards(token, guildsPerShard = 1000) {
     return new Promise((resolve, reject) => {
       if (!token) throw new Error('A token must be provided.');
-      superagent.get(botGateway)
+      superagent.get(Constants.Endpoints.gateway.bot)
         .set('Authorization', `Bot ${token.replace(/^Bot\s*/i, '')}`)
         .end((err, res) => {
           if (err) reject(err);