Restructuring the Community Page

The [Community page](https://graphql.org/community/) has similar issues to the Code page (#911) - there are no guidelines for what should be featured there.

However, with the Community page, I believe there are other considerations. This page was created when GraphQL was newly announced and the exposure was limited. Now there are more books, videos, learning resources, etc. than can be represented on this page.

A community page might still make sense, but we should think about what sections should be included and what the criteria are for the resources featured. This likely wouldn't happen until after the Gatsby migration (#875) is complete, but we can start thinking about it already.

Curious to hear anyone else's thoughts on this!

cc: @IvanGoncharov

まず既存の Community page と関連する Code page issue (#911) を確認し、その後 #875 で参照されている Gatsby migration を検討してください。issue ではファイルやテストは指定されていません。作業が完了するのは、ページ構造と、コミュニティの注目リソースを選定するための明確な基準について合意できた後です。

索引モデルが issue の本文から書いたものです。