feat(templates): add passkeys-backend template

[nicolas-camacho]

Description

Quick deploy template for a sample backend for passkeys using comms API .

Let me know any suggestions or feedback you might have.

Live demo at: https://passkey-demo-5706.twil.io/index.html

Checklist

• [x] I ran npm test locally and it passed without errors.
• [x] I acknowledge that all my contributions will be made under the project's license.