Disclaimer in README.md about non-production readiness

Can we add a disclaimer in the README that NSS should not be used with production data? I've found that it's used in production and marketed as a "secure" place to store your data.

There's already following disclaimer in the index.html file:

This is a prototype implementation of a Solid server. It is a fully functional server, but there are no security or stability guarantees.

I think it serves the purpose of a prototype server well. But I think we should copy this disclaimer to the README to make clear expectations.

(And while it would be nice to get it production ready, I suppose there are not enough resources to make it secure in the near future)

Confronta l'avvertenza esistente in index.html con README.md, iniziando dall'introduzione o dalla descrizione del progetto in README. Il lavoro è completato quando README include chiaramente la stessa avvertenza relativa alla natura di prototipo, alla sicurezza e alla stabilità; non sono indicate modifiche al codice.