prepare FileModel to manage files, cleanup

src/Model/Utility/typeSafety.ts

@@ -3,3 +3,7 @@ export const DATA_VERSION = "v2"
 export function checkIsValidObject(object: any): boolean {
   return object.dataVersion == DATA_VERSION;
 }
+
+export interface ValidObject {
+  dataVersion: "v2";
+}