closes#22015
After adding a passkey, you can now simply login with it directly by
clicking `Sign in with a passkey`.
![Screenshot from 2024-06-26
12-18-17](https://github.com/go-gitea/gitea/assets/6918444/079013c0-ed70-481c-8497-4427344bcdfc)
Note for testing. You need to run gitea using `https` to get the full
passkeys experience.
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Co-authored-by: silverwind <me@silverwind.io>