Tenets:
1. Limit thread names to 15 characters
2. Prefix all Solana-controlled threads with "sol"
3. Use Camel case. It's more character dense than Snake or Kebab case
* client: Remove static connection cache, plumb it instead
* Add TpuClient::new_with_connection_cache to not break downstream
* Refactor get_connection and RwLock into ConnectionCache
* Fix merge conflicts from new async TpuClient
* Remove `ConnectionCache::set_use_quic`
* Move DEFAULT_TPU_USE_QUIC to client, use ConnectionCache::default()
* Update tonic & prost, and regenerate proto
* Reignore doc code
* Revert pull #14367, but pin tokio to v0.2 for jsonrpc
* Bump backoff and goauth -> and therefore tokio
* Bump tokio in faucet, net-utils
* Bump remaining tokio, plus tarpc