Make clientPrerender compatible with CSP

[Marocco2]

Summary

Speculation Rules API should improve website UX thanks to a set of rules that a webdeveloper can write for hinting where the browser should prerender/prefetch a set of pages.
experimental.clientPrerender is a step for automate what rules should be written about for every pages I navigate.
Unfortunately, it won't provide support for dealing with Content Security Policies (CSP): you need to use script-src: 'unsafe-inline' for get this to work, which nullifies the benefits of CSP.

Background & Motivation

https://developer.chrome.com/docs/web-platform/prerender-pages#csp

There are a bunch of methods to write speculation rules. experimental.clientPrerender however is the least CSP compatible of all: it requires a nonce/hash ahead-of-time, along with script-src: 'inline-speculation-rules' to get this to work.
Using netlify-csp-plugin it'll become unfeasible, and Speculation-Rules HTTP header isn't a swissknife solution if you have many different pages around your site

Goals

Astro should provide a bunch of CSP APIs and/or provide some tools that would make writing CSP policies a breeze for a newcomer dev. So, in this instance, Astro would compile AOT every hash that experimental.clientPrerender would generate and pass them on script-src: 'inline-speculation-rules' per page.
Alternatively, it could inject Speculation-Rules HTTP headers with a JSON file for every page in the site (and that would be also cacheable).