Add EventBus, SpeedRunManager, and GhostManager; implement ghost recording and playback features

scripts/GhostFrame.cs

@@ -0,0 +1,9 @@
+using Godot;
+
+namespace Mr.BrickAdventures.scripts;
+
+public partial class GhostFrame : GodotObject
+{
+    public double Timestamp { get; set; }
+    public Vector2 Position { get; set; }
+}