Adding back rest of the menu, ported most of Reflection Inspector for new UI

src/UI/Models/UIPanel.cs

@@ -16,6 +16,8 @@ namespace UnityExplorer.UI.Models
     {
         // STATIC
 
+        internal static void InvokeOnPanelsReordered() => OnPanelsReordered?.Invoke();
+
         public static event Action OnPanelsReordered;
         public static event Action OnClickedOutsidePanels;