Add support for Early Hints using <link> HTML elements

Hi, sending Link HTTP headers is not trivial in many use cases. A much more flexible and convenient approach is using <link> HTML elements. It would be nice if you could add support for Early Hints using preload and preconnect <link> HTML elements. One way to implement this would be using a sort of “Early Hints cache”, using the URL as a key and the preload and preconnect <link> HTML elements as the value. Any client hitting the cache would receive the 103 Early Hints Link headers from Cloudflare Edge. You would need to simply keep the cache up to date parsing the preload and preconnect <link> HTML elements from the response.