Dedupe SendTransactionService(s) (#19354)

* Add new conjoined SendTransactionService

* Remove TODO

* nit A-Z

* Single use statement for banks crates

* Rename new crate

send-transaction-service/src/lib.rs

@@ -0,0 +1,6 @@
+#![allow(clippy::integer_arithmetic)]
+pub mod send_transaction_service;
+pub mod tpu_info;
+
+#[macro_use]
+extern crate solana_metrics;