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/ActionsManager.js

@@ -28,6 +28,7 @@ class ActionsManager {
     this.register(require('./GuildEmojiDelete'));
     this.register(require('./GuildEmojiUpdate'));
     this.register(require('./GuildRolesPositionUpdate'));
+    this.register(require('./GuildChannelsPositionUpdate'));
   }
 
   register(Action) {