Add PRF passkey authenticator support and external passkeys

[iinuwa]

⚠️ This is a draft PR for discussing a proof-of-concept. Detailed review should not be done until this work is refined.

🎟️ Tracking

https://bitwarden.atlassian.net/browse/PM-27582
https://bitwarden.atlassian.net/browse/PM-26177

📔 Objective

This adds the ability to use PRF for passkeys and authenticate using key material tied to a device, not the user key. (We're calling this the "device auth key.") This will effectively allow native clients to act as login+unlock passkeys without requiring vault unlock.

• Incorporates upstream passkey-rs changes
• Adds separate "vault authenticator" and "device authenticator" to distinguish between device-bound flow
• Allows encrypting passkey using a provided external key (device binding key)
• Adds hmacSecret field to FIDO2 credential models

Depends on #494.

⏰ Reminders before review

• Contributor guidelines followed
• All formatters and local linters executed and passed
• Written new unit and / or integration tests where applicable
• Protected functional changes with optionality (feature flags)
• Used internationalization (i18n) for all UI strings
• CI builds passed
• Communicated to DevOps any deployment requirements
• Updated any necessary documentation (Confluence, contributing docs) or informed the documentation
  team

🦮 Reviewer guidelines

• 👍 (:+1:) or similar for great changes
• 📝 (:memo:) or ℹ️ (:information_source:) for notes or general info
• ❓ (:question:) for questions
• 🤔 (:thinking:) or 💭 (:thought_balloon:) for more open inquiry that's not quite a confirmed
  issue and could potentially benefit from discussion
• 🎨 (:art:) for suggestions / improvements
• ❌ (:x:) or ⚠️ (:warning:) for more significant problems or concerns needing attention
• 🌱 (:seedling:) or ♻️ (:recycle:) for future improvements or indications of technical debt
• ⛏ (:pick:) for minor or nitpick changes