Async private key - server side generation

Current implementation sends masterPassword to backend in order to generate the keys, but when decrypting on frontend the encrypted private key is sent along with iv and decrypted client side.

Potential security risk of having to send masterPassword through unsure medium.
Ideally keys should be generated & encrypted client side - then sent over to backend.

Look at the current key generation endpoint and the client-side decryption logic. Understand how masterPassword is currently sent and where private key encryption/decryption happens. The goal is to move key generation and encryption to the frontend before sending to the backend. Check existing API routes and Strapi services for cryptographic operations.

Scritto dal modello di indicizzazione a partire dal testo della issue.