Implemented CMS storage for user and nodes.

Implemented role and permission storage.
Introduced the CMS_PARTIAL_NODE and CMS_PARTIAL_USER.
Added support for node storage extension
  - storage of data specific to each node content type,
  - in addition to the core CMS_NODE)
  - For now, only implemented for SQL storage.
Note: in current version, CMS_PAGE support is hard coded in the core,
    (as opposed to be only supported by the node module.)
Commented/removed for now, the Web API code to update node summary, title, via REST request.

src/service/response/cms_response.e

@@ -268,13 +268,6 @@ feature -- Logging
 --			service.storage.save_log (l_log)
 		end
 
-feature -- Formats
-
-	formats: CMS_FORMATS
-		once
-			create Result
-		end
-
 feature -- Menu
 
 	menu_system: CMS_MENU_SYSTEM