Added support for base_url (i.e the CMS can be hosted on the root, or sub folder).

Local paths are relative to cms site url (i.e no starting slash).
Favor CMS_RESPONSE.absolute_url and url .. instead of using directly WSF_REQUEST.absolute_script_url and script_url.
Handled unicode truncation issue for logger.
Code cleaning.

src/service/misc/cms_url_utilities.e

@@ -13,6 +13,7 @@ inherit
 feature -- Core
 
 	site_url: READABLE_STRING_8
+			-- Absolute site URL of Current CMS site.
 		deferred
 		end