Add Signal to ECS

- Add Signal class to ECS used to send signals/events into systems

CopiumEngine/src/copium/ecs/Signal.cpp

@@ -0,0 +1,10 @@
+#include "copium/ecs/Signal.h"
+
+namespace Copium
+{
+  int Signal::GetAllocatedId()
+  {
+    allocatedIds++;
+    return allocatedIds;
+  }
+}