Implement CSP

[arthurfiorette]

Hono/jsx supports adding CSP headerst to the final script added https://hono.dev/docs/guides/jsx#streamingcontext

Ideally we could also implement the same by simply setting a optional cspNonce optional value in the request context and later inject it in the SuspenseScript.

This could be added automatically or a custom value set by the user

In the fastify plugin, we could either implement this natively or use the fastify-helmet module to generate those on the fly with enableCspNonces: true

https://github.com/fastify/fastify-helmet#example---generate-by-options