Some code refactoring to make it easier on me

Make some collections deserving to be readonly, to be readonly
List within lists contrast a bit better
StringBuilder instead of list of strings
Added dungen's generation stats to debug window

DunGenPlus/DunGenPlus/DevTools/UIElements/TextUIElement.cs

@@ -6,6 +6,7 @@ using System.Threading.Tasks;
 
 namespace DunGenPlus.DevTools.UIElements {
   internal class TextUIElement : BaseUIElement {
-
+    // left empty cause abstract BaseUIElement is abstract, can't be a component
+    // but this can be, and BaseUIElement gives it all the functionality required to work as a simple Text UI Element (as name implies jajajajaja)
   }
 }