Add docs/example of how to do self-hosted GH runners

As a user I would like an example of how to do self-hosted GH runners in my project e.g. see https://dev-portal.diamond.ac.uk/guide/kubernetes/tutorials/arc/.

Should we add a link to these docs (or the example from the docs) to this repo?

首先檢視 repository 現有的文件結構，以及連結的 Diamond Kubernetes ARC tutorial。記錄如何使用 self-hosted GitHub runners，或新增適當的 tutorial link，讓完成後的文件為專案使用者清楚說明設定路徑。

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