Announcing Support for HTTP/2 Server Push

What this post added

This post announces and details Cloudflare's implementation of HTTP/2 Server Push for all customers. It explains the benefits of Server Push for performance, how it works with `PUSH_PROMISE` and `Link` headers, and provides guidance on enabling and disabling it. The post also discusses best use cases, potential downsides, and how to profile Server Push performance using browser developer tools, highlighting Cloudflare's role as a pioneer in deploying this feature at scale.