QfqForm.js: support 'hidden' attribute when configuring form elements.

javascript/src/QfqForm.js

@@ -641,7 +641,10 @@ var QfqNS = QfqNS || {};
                 if (configurationItem.disabled !== undefined) {
                     // Readonly and disabled is the same in our domain
                     element.setEnabled(!configurationItem.disabled);
+                }
 
+                if (configurationItem.hidden !== undefined) {
+                    element.setHidden(configurationItem.hidden);
                 }
             } catch (e) {
                 n.Log.error(e.message);