Role archives and history page

From @astrofrog:

> Somewhere (doesn't have to be too obvious necessarily) we should keep a list of people who were previously in roles, so that there is an official place we record this (because I think we should recognize past as well as current contributions)

未指定任何文件、测试或入口点。检查现有的角色页面和网站导航，以确定历史列表应放置在哪里，然后与 maintainer 确认预期的人员、角色和呈现方式；当过去的角色持有人拥有一个官方且易于发现的历史页面时，即表示完成。

由索引模型根据 Issue 内容生成。