feat(curd): add relation data binding and optimize model construction

- Add relation data binding in model construction
- Update model template to include new relation construction logic
- Remove unused index method template

app/admin/service/curd/templates/controller/indexMethod.code

@@ -1,23 +0,0 @@
-
-    /**
-     * @NodeAnnotation(title="列表")
-     */
-    public function index()
-    {
-        if ($this->request->isAjax()) {
-            if (input('selectFields')) {
-                return $this->selectList();
-            }
-            list($page, $limit, $where) = $this->buildTableParams();
-            $count = $this->model{{relationIndexMethod}}->where($where)->count();
-            $list = $this->model{{relationIndexMethod}}->where($where)->page($page, $limit)->order($this->sort)->select()->toArray();
-            $data = [
-                'code'  => 0,
-                'msg'   => '',
-                'count' => $count,
-                'data'  => $list,
-            ];
-            return json($data);
-        }
-        return $this->fetch();
-    }