A good day to trie-hard: saving compute 1% at a time

Introduced a new open-source Rust crate, `trie-hard`, which implements a trie data structure optimized for high-throughput string lookups. This new implementation reduced the CPU utilization of the `clear_internal_headers` function in pingora-origin from 1.71% to 0.34% in production, achieving a significant compute saving by optimizing the process of removing internal headers from HTTP requests.