Make Audio Alerts Configurable

The new Alert feature, which sounds a 'yelp' upon web client connect and Chat window activity, needs very much to be a configurable election and not default behavior. When Chat is enabled in a webinar, or indeed a conference context, the constant yelping as parallel chat activity posts in the window is extremely distracting to presenters and to audience/participants. Priority Major as the workaround-to find and delete the chat_message.mp3 file under the webapps/public folder-is not viable for many OM users. Ideally, this election should be a user preference rather than a server/system setting.