Rename some template functions internal terms

* credentials => user_org
* private => superuser

client/renderer/interface.yaml

@@ -428,21 +428,21 @@
     - { name: service,  type: "text" }
 
 - name: cdb_service_set_user_rate_limit
-  private: true
+  superuser: true
   return_type: void
   params:
     - { name: service,  type: "text" }
     - { name: rate_limit, type: json }
 
 - name: cdb_service_set_org_rate_limit
-  private: true
+  superuser: true
   return_type: void
   params:
     - { name: service,  type: "text" }
     - { name: rate_limit, type: json }
 
 - name: cdb_service_set_server_rate_limit
-  private: true
+  superuser: true
   return_type: void
   params:
     - { name: service,  type: "text" }