Seperate frontend from backend, move js into file

Since the df plugin process and the actual web code run in their own
seperate processes (I think?) it makes sense to seperate them properly.
This way, anybody interested in _just_ added something to frontend
doesn't have to wade through the plugin to find it. Also: the inline
javascript has been moved into a seperate file, js/webfort.js and
reformatted, so people can start hacking on it directly.