feat(Extensions): Add prf extension interfaces

[tarekbeb]

This pull request introduces new interfaces and properties to support the PRF (Pseudorandom Function) extension in WebAuthn authentication flows. It adds:

• AuthenticationExtensionsPRFValues
• AuthenticationExtensionsPRFInputs
• AuthenticationExtensionsPRFOutputs
• Updated AuthenticationExtensionsClientInputs and AuthenticationExtensionsClientOutputs with the prf inputs and outputs respectively.

How to use:

const pubKeyCredential: PublicKeyCredential = credential;
const clientExtensions = credential.getClientExtensionResults()
const isPrfEnabled = clientExtensions.prf?.enabled
const prfValue = new Uint8Array(extensions.prf.results?.first);

Once the prf value is obtained, a CryptoKey can be derived to be used in the browser to encrypt/decrypt data. (https://blog.millerti.me/2023/01/22/encrypting-data-in-the-browser-using-webauthn/)

PRF Specification:
https://www.w3.org/TR/webauthn-3/#prf-extension

[MasterKale]

Hello @tarekbeb as per the README this project is not open to external PRs. I am more than happy to continue this conversation over in the issue you created, though (thank you for that 🙏)