Feature/autodeploy testing

Updates to allow ab_testing project to be deployed via ansible/Jenkins in AWS.  Some changes:
- give project urls consistent and unique prefix of 'ab-testing/'
- add console and file logging to test/qa settings files
- add gunicorn and redis as requirements in relevant environments
- update static url and file finder
- move secure_proxy_ssl_header setting to base settings
- update supervisor.conf.j2 template to use djang_settings variable