maint: add demo world loader

Assets/Scripts/World/DemoWorldLoader.cs

@@ -0,0 +1,22 @@
+using System.Collections.Generic;
+using UnityEngine;
+using UnityEngine.SceneManagement;
+
+public class DemoWorldLoader : MonoBehaviour{
+    public List<string> scenesName;
+    
+    void Start()
+    {
+        foreach (string thisScene in scenesName) {
+            if (!SceneManager.GetSceneByName(thisScene).isLoaded) {
+                SceneManager.LoadScene(thisScene, LoadSceneMode.Additive);
+            }
+        }    
+    }
+
+    // Update is called once per frame
+    void Update()
+    {
+        
+    }
+}