WebAuthn / FIDO2 / 2fa: allow discoverable or non-discoverable passkeys

[swissbit-eis-admin]

• Let users choose during registration whether a passkey is stored as a discoverable credential; retry with the legacy flow if the authenticator can't do resident keys.
• Simplify “Log in with a device”: a single field now accepts an optional login/email, using discoverable credentials when left empty and falling back gracefully otherwise.
• Backend/WebAuthn services updated to handle optional usernames and return the credential source so the UID can be derived from the authenticator.

Please refer to PR to stable32: #57154
Both have similar function

Summary

This allows user to register discoverable and non-discoverable FIDO2 passkeys in user settings.
If user tries to login with second factor and omits email login -> discoverable credential attempted
if user fills in email at login -> classic host side credentials are used.

TODO

• ...

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)
• Labels added where applicable (ex: bug/enhancement, 3. to review, feature component)
• Milestone added for target branch/version (ex: 32.x for stable32)

[swissbit-eis-admin]

@ChristophWurst can you give me feedback to my PR?

The idea was to extend Passkey Support by discoverable credentials (new), keep existing functionality for existing password less login (keep) and rephrase the technical wording (webauthn) to a more standard user centric view (modified).
Some EU and South America internationalisation is provided as well.
The commits show the stages of improvement.

Thank you.

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