[new]增加指代消解源码

[Xiaoxiong-Liu]

Description：增加了指代消解论文复现的源代码。

Main reason: 增加复现模块。

Checklist 检查下面各项是否完成

Please feel free to remove inapplicable items for your PR.

• [ ✅] The PR title starts with [$CATEGORY] (例如[bugfix]修复bug，[new]添加新功能，[test]修改测试，[rm]删除旧代码)
• [ ✅] Changes are complete (i.e. I finished coding on this PR) 修改完成才提PR
• All changes have test coverage 修改的部分顺利通过测试。对于fastnlp/fastnlp/的修改，测试代码必须提供在fastnlp/test/。
• [✅] Code is well-documented 注释写好，API文档会从注释中抽取
• To the my best knowledge, examples are either not affected by this change, or have been fixed to be compatible with this change 修改导致例子或tutorial有变化，请找核心开发人员

Changes: 逐项描述修改的内容

• 增加指代消解源码

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