Add new methods to input handler, add RectangleShape2d, modify test game.

DaggerFramework/Source/SceneGraph/Entities/RectangleShape2d.cs

@@ -0,0 +1,14 @@
+using System.Numerics;
+using DaggerFramework.Rendering;
+
+namespace DaggerFramework.SceneGraph;
+
+public class RectangleShape2d : Drawable2d
+{
+    public Vector2 Size { get; set; } = Vector2.One * 32;
+    public Color Color { get; set; } = Color.White;
+    public override void OnDraw(Renderer renderer)
+    {
+        renderer.DrawRectangle(Size, Color);
+    }
+}