[api] read download_url and ymp_url from configuration

src/api/app/helpers/public_helper.rb

@@ -1,9 +1,9 @@
 module PublicHelper
   def download_url(path)
-     path ? File.join(CONFIG['download_url'], path) : ""
+     path ? File.join(Configuration.download_url, path) : ""
   end
 
   def ymp_url(path)
-     path ? File.join(CONFIG['ymp_url'], path) : ""
+     path ? File.join(Configuration.ymp_url, path) : ""
   end
 end

src/api/app/models/configuration.rb

@@ -48,6 +48,15 @@ def anonymous?
     def registration
       Configuration.limit(1).pluck(:registration).first
     end
+
+    def download_url
+      Configuration.limit(1).pluck(:download_url).first
+    end
+
+    def ymp_url
+      Configuration.limit(1).pluck(:ymp_url).first
+    end
+
   end
 
   def update_from_options_yml()