This is needed when we want people to try out the extension on actual (non-beta cluster) Wikipedia. It will enable automatically for users who wants that and enables statistics about how much a feature is used.
This includes adding image and description for the beta preferences, and creating a hook function (Exampel code can be found in TimedMediaHandler).
During beta the "enable this beta feature" setting should take preference over the normal "enable" setting in Wikispeech, so that you don't have to activate it twice.