Remove hardcoded CORS_ORIGIN default - must be set via env

docker-compose.stack.yml

@@ -26,7 +26,7 @@ services:
       - LDAP_UPN_SUFFIX=${LDAP_UPN_SUFFIX:-}
       - ADMIN_EMAIL=${ADMIN_EMAIL:-admin@workflow.local}
       - ADMIN_INIT_PASSWORD=${ADMIN_INIT_PASSWORD:-}
-      - CORS_ORIGIN=${CORS_ORIGIN:-http://localhost:5000}
+      - CORS_ORIGIN=${CORS_ORIGIN:-}
       - NODE_ENV=${NODE_ENV:-production}
       - DATABASE_URL=postgresql://${POSTGRES_USER:-workflow}:${POSTGRES_PASSWORD:-workflow}@db:5432/${POSTGRES_DB:-workflow}
       - SESSION_MAX_PER_USER=${SESSION_MAX_PER_USER:-5}