Gantt: move files to .ts (ui.gantt.js)

Author: pharret31

packages/devextreme/js/ui/gantt/ui.gantt.js renamed to packages/devextreme/js/__internal/ui/gantt/ui.gantt.ts

@@ -1,4 +1,5 @@
-import Gantt from './gantt/ui.gantt';
+import Gantt from '../__internal/ui/gantt/ui.gantt';
+
 export default Gantt;
 
 /**