Implement 'Modify Guild Channel Positions' (#1198)

* Adding shuffleArray method to utils

* Shuffle channels functionality on guild.

* Comment fix

* Removing shuffle functionality and replacing with a simple update

* Code review changes to method/variable names

* Update comment reference to channelId as well

* Updating jsdoc with typedef of ChannelPosition

src/client/actions/GuildChannelsPositionUpdate.js

@@ -0,0 +1,23 @@
+const Action = require('./Action');
+
+class GuildChannelsPositionUpdate extends Action {
+  handle(data) {
+    const client = this.client;
+
+    const guild = client.guilds.get(data.guild_id);
+    if (guild) {
+      for (const partialChannel of data.channels) {
+        const channel = guild.roles.get(partialChannel.id);
+        if (channel) {
+          channel.position = partialChannel.position;
+        }
+      }
+    }
+
+    return {
+      guild,
+    };
+  }
+}
+
+module.exports = GuildChannelsPositionUpdate;