Set default emails.

Without this, the defaults get set to '' and then sentences on the site look weird because the emails are missing.

playbooks/roles/edxapp/defaults/main.yml

@@ -92,13 +92,13 @@ EDXAPP_CMS_NGINX_PORT: 18010
 EDXAPP_LANG: 'en_US.UTF-8'
 EDXAPP_TIME_ZONE: 'America/New_York'
 
-EDXAPP_TECH_SUPPORT_EMAIL: ''
-EDXAPP_CONTACT_EMAIL: ''
-EDXAPP_BUGS_EMAIL: ''
-EDXAPP_DEFAULT_FROM_EMAIL: ''
-EDXAPP_DEFAULT_FEEDBACK_EMAIL: ''
-EDXAPP_SERVER_EMAIL: ''
-EDXAPP_BULK_EMAIL_DEFAULT_FROM_EMAIL: ''
+EDXAPP_TECH_SUPPORT_EMAIL: 'technical@example.com'
+EDXAPP_CONTACT_EMAIL: 'info@example.com'
+EDXAPP_BUGS_EMAIL: 'bugs@example.com'
+EDXAPP_DEFAULT_FROM_EMAIL: 'registration@example.com'
+EDXAPP_DEFAULT_FEEDBACK_EMAIL: 'feedback@example.com'
+EDXAPP_SERVER_EMAIL: 'devops@example.com'
+EDXAPP_BULK_EMAIL_DEFAULT_FROM_EMAIL: 'no-reploy@example.com'
 
 EDXAPP_ENV_EXTRA: {}
 EDXAPP_AUTH_EXTRA: {}