Removed obsolete calls, harmonized predefine response, added non admin user pages.

When access is denied, also provide when possible and wanted, the needed
permissions so that in the future, user will be able to ask for
permission easily.
Renamed previous user handlers as admin user handlers.
Added non admin user handler /user/{uid} .
Add new `send_...` response to `CMS_API.response_api`, and use them
instead of `create {...RESPONSE}.... ; execute`.
Fixed potential issue with storage mailer initialization if folder does
not exist.
Added utf_8_encoded helpers function on CMS_API interface.
Fixed a few unicode potential issues.
Removed a few obsolete calls.

modules/blog/handler/blog_user_handler.e

@@ -37,8 +37,6 @@ feature -- HTTP Methods
 
 	do_get (req: WSF_REQUEST; res: WSF_RESPONSE)
 			-- <Precursor>
-		local
-			l_error: NOT_FOUND_ERROR_CMS_RESPONSE
 		do
 			check user_void: user = Void end
 			if attached user_from_request (req) as l_user then
@@ -47,13 +45,11 @@ feature -- HTTP Methods
 				Precursor (req, res)
 			else
 					-- Throw a bad request error because the user is not valid
-				create l_error.make (req, res, api)
 				if attached user_parameter (req) as l_user_id then
-					l_error.set_main_content ("<h1>Error</h1>User with id " + api.html_encoded (l_user_id) + " not found!</h1>")
+					api.response_api.send_not_found ("<h1>Error</h1>User with id " + api.html_encoded (l_user_id) + " not found!</h1>", req, res)
 				else
-					l_error.set_main_content ("<h1>Error</h1>User not found!</h1>")
+					api.response_api.send_not_found ("<h1>Error</h1>User not found!</h1>", req, res)
 				end
-				l_error.execute
 			end
 			user := Void
 		end