Make SSL boring again

What this post added

This post details Cloudflare's migration of its edge SSL connection termination stack to BoringSSL. This move enabled support for TLS 1.3 across the board, improved key negotiation with X25519 for TLS 1.2 and earlier, and introduced RSA-PSS for TLS 1.2. It also highlights internal improvements to features like Keyless SSL, distributed session ID caches, and cipher grouping, as well as the development of a more reliable OCSP stapling pipeline. The post also touches on addressing performance issues with base64 decoding in BoringSSL and maintaining support for legacy ChaCha20-Poly1305 ciphers for older clients.