g6 legend api不支持图片和自定义节点，可通过其他方式实现吗？ #3275

• I have searched the issues of this repository and believe that this is not a duplicate.

What problem does this feature solve?

增加各种样式的图例，方便过滤和检索

What does the proposed API look like?

支持更多自定义节点和图片图例

<!-- generated by antv-issue-helper. DO NOT REMOVE -->