调整服务器逻辑

1、调整Entity.AddComponent方法添加的组件Id为父组件的Id。
2、增加了ISupportedSingleCollection和ISingleCollectionRoot接口.
3、增加了SingleCollection、用于把子组件保存到单独的数据库表的功能，配合ISupportedSingleCollection和ISingleCollectionRoot。

Assets/GameScripts/DotNet/Core/Entitas/Entity.cs

@@ -321,7 +321,7 @@ namespace TEngine
 
         public T AddComponent<T>() where T : Entity, new()
         {
-            var entity = Create<T>(Scene.RouteId, false);
+            var entity = Create<T>(Id, Scene.RouteId, false);
             AddComponent(entity);
             EntitiesSystem.Instance.Awake(entity);
             EntitiesSystem.Instance.StartUpdate(entity);
@@ -367,6 +367,12 @@ namespace TEngine
             }
             else
             {
+#if TENGINE_NET
+                if (component is ISupportedSingleCollection && component.Id != Id)
+                {
+                    Log.Error($"component type :{component.GetType().FullName} for implementing ISupportedSingleCollection, it is required that the Id must be the same as the parent");
+                }
+#endif
                 if (_tree == null)
                 {
                     _tree = DictionaryPool<Type, Entity>.Create();
@@ -404,6 +410,8 @@ namespace TEngine
         #endregion
 
         #region GetComponent
+        
+        public DictionaryPool<Type, Entity> GetTree => _tree;
 
         public T GetComponent<T>() where T : Entity, new()
         {