Add ecs ComponentListener

- Add ecs ComponentListener which listens to Component addition and
  removal
- Add RefCounter class used to keep track of moves and copies

CopiumEngine/src/copium/ecs/ComponentPoolBase.h

@@ -15,7 +15,6 @@ namespace Copium
     virtual ~ComponentPoolBase() = default;
 
     virtual size_t Size() = 0;
-    virtual void Pop() = 0;
     virtual bool Erase(EntityId entity) = 0;
     std::vector<EntityId>& GetEntities();
     const std::vector<EntityId>& GetEntities() const;