- add a cats.authentication.ClientCertificateBackend authentication
backend implementation that extracts the used fields from a client
certificate
- configure the AUTHENTICATION_BACKENDS setting to use the
ClientCertificateBackend
- add cryptography dependency to parse certificate data
- add gunicorn as production dependency
- add a development configuration for Gunicorn
- document how to pass client certificate information via nginx reverse
proxy
- add a certificate_login view and a basic home_page view and add
corresponding URL patterns
- ignore PEM encoded files and temporary gunicorn files
