Move application to /app

* Protect /app and /api with Raven.
* Simple initial welcome page.
* Delete previous LoginController.
* Move JS files to /web

I changed the `Application.js` config but it's still trying to load the file relatively. Any ideas what might be causing this, @rh389? Quite possible I've not configured it correctly!

Also, I'm not convinced these changes were everything that you needed to be done to deal with logins from the frontend. Let me know what else needs to be done.