BE - Create a webauthn-passkeys concern

Context

Helper methods to honour 2FA flow business logic in backend & frontend needs

Implementation Plan

• List of passkeys
• List of webauthn keys
• List of both webauthn & passkeys
• passkey_vars_for_view (Based on app/helpers/device_registration_helper.rb vars) for the /accounts table
• Webauthn enabled & disabled status
• Passkey enabled & disabled status
• Tests