Rich, complex rules for advanced load balancing

Introduced a custom rule builder for Cloudflare Load Balancing, allowing users to define complex traffic steering logic using 'and' and 'or' statements. This feature leverages the open-source wirefilter execution engine, providing a familiar syntax for users of Firewall Rules. The post details use cases for path-based routing, header-based steering, and split-horizon DNS setups, and explains the differences in available fields between DNS and proxied load balancing modes.