Requesting index.html from root will serve the data browser, not the file itself

Based on https://github.com/solid/userguide/pull/7 I became aware that if you request index.html from the root of a storage, it will return the HTML for the data browser instead of the index.html file itself.

E.g. https://megoth.solid.community/ will give another response than https://megoth.solid.community/index.html. The latter is a handy bug for people who want to edit the index.html file though, so before fixing this bug we need to make sure that users have the ability to edit index.html via the data browser using other means.

With the fix in https://github.com/solid/node-solid-server/pull/1341 we do get this feature though, as users can fetch the contents of index.html through "Your stuff" in the Dashboard. This paves the way for a fix for this bug, which would result in the correct HTML being returned, which is also good for the Source, which will show the correct HTML instead of the default HTML for the data browser.

审查 node-solid-server pull request 1341 以及对存储根目录和 /index.html 的请求处理。确认用户仍可通过 Dashboard 中的 Your stuff 获取 index.html，然后验证根目录请求和 Source 显示的是文件的 HTML，而不是数据浏览器的 HTML。