First step towards denying clippy::integer_arithmetic (bp #15366) (#15381)

* CI: Globally deny clippy::integer_arithmetic lint

(cherry picked from commit 7035e8485c)

* Re-allow clippy::integer_arithmetic at crate-level

(cherry picked from commit 7f7370c306)

# Conflicts:
#	bench-tps/tests/bench_tps.rs

Co-authored-by: Trent Nelson <trent@solana.com>

net-utils/src/lib.rs

@@ -1,4 +1,5 @@
 //! The `net_utils` module assists with networking
+#![allow(clippy::integer_arithmetic)]
 use {
     log::*,
     rand::{thread_rng, Rng},