Sdk: start to appease clippy's integer arithmetic check (#15736)

* Move to module-level clippy allowance

* Fix stake_weighted_timestamp math

* Fix genesis_config

* Fix shred_version

* Fix hard_forks

* Fix process_instruction

* Add ArithmeticOverflow ix error

* Fix nonce_keyed_account

* Update BankSlotDelta frozen abi due to new ix error

sdk/src/hard_forks.rs

@@ -18,7 +18,7 @@ impl HardForks {
             .iter()
             .position(|(slot, _)| *slot == new_slot)
         {
-            self.hard_forks[i] = (new_slot, self.hard_forks[i].1 + 1);
+            self.hard_forks[i] = (new_slot, self.hard_forks[i].1.saturating_add(1));
         } else {
             self.hard_forks.push((new_slot, 1));
         }