Add enterprise tagline to edxapp.

CHANGELOG.md

 - Role: edxapp
+  - Added `EDXAPP_ENTERPRISE_TAGLINE` for customized header taglines for different enterprises.
+
+- Role: edxapp
   - Added `ENTERPRISE_SUPPORT_URL` variable used by the LMS.
 
 - Role: edxapp

playbooks/roles/edxapp/defaults/main.yml

@@ -730,6 +730,8 @@ EDXAPP_ENTERPRISE_ENROLLMENT_API_URL: "{{ EDXAPP_LMS_ROOT_URL }}/api/enrollment/
 
 EDXAPP_ENTERPRISE_SUPPORT_URL: ''
 
+EDXAPP_ENTERPRISE_TAGLINE: ''
+
 # The assigned ICP license number for display in the platform footer
 EDXAPP_ICP_LICENSE: !!null
 
@@ -1210,6 +1212,7 @@ lms_env_config:
   ACE_CHANNEL_SAILTHRU_DEBUG: "{{ EDXAPP_ACE_CHANNEL_SAILTHRU_DEBUG }}"
   ACE_CHANNEL_SAILTHRU_TEMPLATE_NAME: "{{ EDXAPP_ACE_CHANNEL_SAILTHRU_TEMPLATE_NAME }}"
   ACE_ROUTING_KEY: "{{ EDXAPP_ACE_ROUTING_KEY }}"
+  ENTERPRISE_TAGLINE: "{{ EDXAPP_ENTERPRISE_TAGLINE }}"
 
 cms_auth_config:
   <<: *edxapp_generic_auth