REST related mods that loads an Application with an @ApplicationPath and does not require web.xml

merge changes required to load a web.xml and application named in the web.xml. Currently web.xml is hardcoded in ServingLayer.java but should probably be specified via a config param.
(You can just push more commits to your work branch to update this PR, if you like. In this case it's your master.)

It's sounding like we need that `OryxApplication` back again, and go back to the `application-package` approach. That works, makes sense for end-users, and only unfortunately means a compile dependency on Jersey.

I think we don't need to worry about `web.xml`. If we need to write one for some reason to support a .war deployment, we'll just do that separately. 

Packaging a .war seems possible here too as it's just a matter of bundling the same classes and leaving it to the user to edit web.xml if they must -- there's no way around that, it's just how JEE works. It's not a primary deployment model I am worried about anyhow, and I'm not concerned that there's a big reason this won't work elsewhere. Later we can tweak it if needed.

Shall we talk about this soon? and/or Kam feel free to fire again with a PR considering all of this discussion.