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.

從 reactnavigation.org/docs/auth-flow 的 auth-flow 文件開始，並查看連結的 ORY Kratos React Native 參考專案。檢查 ORY Kratos 區段是否適合現有的指南結構，並根據所參考的專案核實設定細節。當文件提供一份清楚、準確的 ORY Kratos 串接 React Native 指南時，即視為完成。