Add guide for setting up Auth with open source ORY Kratos

I used the React Navigation guide on auth quite extensively when writing the reference for writing how to wire the open source ORY Kratos project into React Native, the result of which can be found at https://github.com/ory/kratos-selfservice-ui-react-native.

I was wondering if it would be of interest/worth to add a section to the auth documentation covering a setup with ORY Kratos and React Native, given that both projects are open source, have a broad community, and are well maintained. I think it could help developers getting into React Native Navigation / React Native solve auth easier and with less frustration and by using Apache 2.0 licensed open source only.

I'd also be happy to check into other projects such as KeyCloak to provide a guide, however the OAuth2 set up makes this much more difficult to nail down in a couple of sections - so this could probably take a bit of time.

reactnavigation.org/docs/auth-flow の認証フローのドキュメントから始め、リンクされている ORY Kratos React Native のリファレンスプロジェクトを確認します。既存のガイド構成に ORY Kratos のセクションが適合するか確認し、参照先プロジェクトに照らしてセットアップの詳細を検証します。ドキュメントが ORY Kratos を React Native に組み込むための明確で正確なガイドを提供できれば完了です。