移除非必须，和lite同步

ibzdst-core/src/main/java/cn/ibizlab/core/lite/extensions/service/LiteModelService.java

 package cn.ibizlab.core.lite.extensions.service;
 
-import cn.ibizlab.core.extensions.domain.AssembleModel;
 import cn.ibizlab.core.lite.domain.DstApp;
 import cn.ibizlab.core.lite.domain.DstSystem;
 import cn.ibizlab.core.lite.domain.MetaEntity;
@@ -312,14 +311,5 @@ public class LiteModelService {
         out.close();
     }
 
-    public String exportFile(List<MetaModel> model){
-        List<AssembleModel> temp = new ArrayList<>();
-        for (MetaModel ignored : model) {
-            temp.add(null);
-        }
-        String json = JSON.toJSONString(temp);
-        String fileName = this.saveFile(json);
-        return fileName;
-    }
 
 }