Include CORS_ORIGIN_WHITELIST in programs defaults

This will allow us to configure whitelisted domains/hostnames for stage and production.

playbooks/roles/programs/defaults/main.yml

@@ -49,6 +49,10 @@ PROGRAMS_SOCIAL_AUTH_REDIRECT_IS_HTTPS: false
 
 PROGRAMS_PLATFORM_NAME: 'Your Platform Name Here'
 
+# CORS
+# See: https://github.com/ottoyiu/django-cors-headers/.
+PROGRAMS_CORS_ORIGIN_WHITELIST: []
+
 PROGRAMS_SERVICE_CONFIG:
   SECRET_KEY: '{{ PROGRAMS_SECRET_KEY }}'
   TIME_ZONE: '{{ PROGRAMS_TIME_ZONE }}'
@@ -68,6 +72,7 @@ PROGRAMS_SERVICE_CONFIG:
 
   PLATFORM_NAME: '{{ PROGRAMS_PLATFORM_NAME }}'
 
+  CORS_ORIGIN_WHITELIST: '{{ PROGRAMS_CORS_ORIGIN_WHITELIST }}'
 
 PROGRAMS_REPOS:
   - PROTOCOL: "{{ COMMON_GIT_PROTOCOL }}"