Engage should use a single app/servlet approach to reduce duplication among handlers and resolve problems with URL routing.

At the moment, Engage is structured awkwardly, causing problems with URL routing and more. We register each Engage handler (artifact View, browse, and each of their couch data feeds) as separate servlets in web.xml, then creating separate Kettle apps for each.

In practice, we should have a single Kettle app for the whole of Engage, and each of the handler logic should be initialized by the app or the framework.

Mounting shared resources such as Infusion or Engage Client should also be done once in the App, not in each handler init.