chore: coroutine manager moved to correct directory

Engine.Core/Systems/CoroutineYield.cs

@@ -0,0 +1,10 @@
+using System;
+
+namespace Engine.Core;
+
+public class CoroutineYield(Func<bool> condition) : ICoroutineYield
+{
+    private readonly Func<bool> condition = condition;
+
+    public bool Yield() => condition.Invoke();
+}