Pulled s3 policy creation into main server

Moved the s3 policy creation route into the main server from the image
cdn server. This is to avoid issuing CORS from the image cdn server.
Also, authentication and configurations can all be kept on ther main
server.

The image cdn server was also updated to handle s3 uploaded image urls.
The image cdn server also replaced request with hapi.proxy because it
can be set to pass along the header from s3. The image module has also
switched to sha1 for image method param generation and the handling of
the image proxying has been tighten up a little bit as well.