[NOJIRA] Reconfigured default CAS sever to use UC Berkeley Test CAS

The README instructs users to create ~/.calcentral_config and populate it with config/settings.yml, and config/settings/*.yml. 

By default, the ~/.calcentral_config/settings.local.yml has localhost:1234 configured as the CAS server, resulting in error. This PR is updating the default CAS Server config to use the UC Berkeley CAS auth testing server.