Switch leader scheduler to use PoH ticks instead of Entry height (#1519)

* Add PoH height to process_ledger()

* Moved broadcast_stage Leader Scheduling logic to use Poh height instead of entry_height

* Moved LeaderScheduler logic to PoH in ReplicateStage

* Fix Leader scheduling tests to use PoH instead of entry height

* Change is_leader detection in repair() to use PoH instead of entry height

* Add tests to LeaderScheduler for new functionality

* fix Entry::new and genesis block PoH counts

* Moved LeaderScheduler to PoH ticks

* Cleanup to resolve PR comments

src/replicator.rs

@@ -108,6 +108,7 @@ impl Replicator {
         let t_window = window_service(
             cluster_info.clone(),
             shared_window.clone(),
+            0,
             entry_height,
             max_entry_height,
             blob_fetch_receiver,