Removed the old Memory Arena and converted all to the new one

Game/Entity/EntityManager.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #include <Core/Common/CoreTypes.h>
+#include <Core/Container/Vector.h>
 
 namespace Game
 {
@@ -10,10 +11,14 @@ namespace Game
     struct EntityManager
     {
         static EntityID ID;
-        // May be this should contains the allocator for each entity types
+
+        Juliet::Arena* Arena;
+        // TODO: Should be a pool
+        Juliet::VectorArena<Entity, 1024> Entities;
     };
 
-    void           InitEntityManager();
+    void           InitEntityManager(Juliet::NonNullPtr<Juliet::Arena> arena);
+    void           ShutdownEntityManager();
     EntityManager& GetEntityManager();
     void           RegisterEntity(EntityManager& manager, Entity* entity);
 } // namespace Game