Feat custom user

[FreddyDevelop]

Description

Add custom user id to a user. This custom user id is only used for verifying assertions from imported passkeys.
New passkeys are created with the user id (uuid) from Hanko.

Implementation

Added a new column to the user table. Check in WebauthnService.VerifyAssertionResponse if the userHandle in the response is a uuid, if not treat it as a custom user id. Get the user based on the custom user ID and verify the response against the user credentials.
Also return the custom user id in the JWT.

Tests

• Create a passkey for a user with an user which is not a uuid. (E.g. with https://github.com/teamhanko/passkeys)
• Copy the webauthn credential into the database (currently there is no other way to import a webauthn credential)
• Associate the credential to an existing user or create a new user
• Add the custom user id to the user
• Try to login using this new credential

Keep in mind that the webauthn credential must be created and used with the same RP ID.

Todos

• Extend the user import to also import a custom user id

Additional context

This is needed when a relying party already has implemented passkeys, but wants to migrate to Hanko and does not use uuids as user identifiers.