settings: Add django.contrib.staticfiles to the project

This is needes to serve the admin static files.

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
settings: Use the Django debug toolbar

I'd like to see how many requests are done per page to make sure what
I'm doing doesn't result in yet another request.

The toolbar will only be active if DEBUG = True.

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>