Integrate 'django.contrib.staticfiles'

Integrate 'django.contrib.staticfiles'

Rather than providing a custom solution for serving static files, use
the solution provided in the upstream Django source.

This allows us to remove the top-level 'urls.py' file.

Signed-off-by: Stephen Finucane <stephenfinucane@hotmail.com>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>