拖拽出来的都是单个表单项，想要实现自定义表单项

## 复现截图
现有效果：

想要如下效果： 💯

## 复现流程与链接

[lowcode demo]()中场景“antd 高级组件 + formily 表单组件"，想要自定义类似 [antd 自定义组件](https://ant.design/components/form-cn/#components-form-demo-customized-form-controls)效果的表单项。

## 期望结果

lowcode提供一种方式实现自定义表单项，onChange的时候是一个对象。

## 环境信息

- 引擎版本 1.0.11
- ext 版本 1.0.3
- 物料
- moment﹫2.24.0
- lodash
- iconfont-icons
- ﹫ant-design/icons﹫4.7.0
- antd﹫4.19.5
- ﹫alifd/next﹫1.24.18
- ﹫alilc/antd-lowcode-materials﹫1.0.6
- ﹫seada/antd-materials﹫0.1.1
- ﹫seada/formily-materials﹫0.1.1

Start with the lowcode demo scene “antd 高级组件 + formily 表单组件” and compare its current single-item drag behavior with the linked Ant Design customized form controls example. Define the integration point for custom form items and verify that changing the item produces an object value as requested.

Written by the indexing model from the issue text.