Add NotificationManager and NotificationLabel for age advancement notifications; refactor scripts into Components directory

Scripts/NotificationLabel.cs

@@ -0,0 +1,20 @@
+using Godot;
+
+namespace ParasiticGod.Scripts;
+
+[GlobalClass]
+public partial class NotificationLabel : Label
+{
+    public void ShowNotification(string text)
+    {
+        Text = text;
+        PivotOffset = Size / 2;
+        GlobalPosition = GetViewportRect().Size / 2;
+
+        var tween = CreateTween();
+        tween.TweenProperty(this, "modulate:a", 1.0f, 0.5f).From(0.0f);
+        tween.TweenInterval(2.5f);
+        tween.TweenProperty(this, "modulate:a", 0.0f, 1.0f);
+        tween.Finished += QueueFree;
+    }
+}