Additional credentials updates

- Added missing variables for demo data command
- Updated changelog

LEARNER-816

CHANGELOG.md

+- Role: credentials
+  - This role is now dependent on the edx_django_service role. Settings are all the same, but nearly all of the tasks are performed by the edx_django_service role.
+
 - Role: veda_delivery_worker
   - New role added to run [video delivery worker](https://github.com/edx/edx-video-pipeline/blob/master/bin/deliver)
 

playbooks/roles/credentials/defaults/main.yml

@@ -153,6 +153,10 @@ CREDENTIALS_AUTOMATED_USERS: {}
 
 credentials_create_demo_data: false
 
+# NOTE: These variables are only needed to create the demo site (e.g. for sandboxes)
+CREDENTIALS_LMS_URL_ROOT: !!null
+CREDENTIALS_DISCOVERY_API_URL:  !!null
+
 credentials_post_migrate_commands:
   - command: './manage.py create_or_update_site --site-id=1 --site-domain={{ CREDENTIALS_DOMAIN }} --site-name="Open edX" --platform-name="Open edX" --company-name="Open edX" --lms-url-root={{ CREDENTIALS_LMS_URL_ROOT }} --catalog-api-url={{ CREDENTIALS_DISCOVERY_API_URL }} --tos-url={{ CREDENTIALS_LMS_URL_ROOT }}/tos --privacy-policy-url={{ CREDENTIALS_LMS_URL_ROOT }}/privacy --homepage-url={{ CREDENTIALS_LMS_URL_ROOT }} --certificate-help-url={{ CREDENTIALS_LMS_URL_ROOT }}/faq --theme-name=openedx'
     when: '{{ credentials_create_demo_data }}'