Add solana-ledger crate (#6415)

automerge

ledger/src/lib.rs

@@ -0,0 +1,12 @@
+#[macro_use]
+pub mod blocktree;
+pub mod entry;
+pub mod erasure;
+pub mod genesis_utils;
+pub mod leader_schedule;
+pub mod leader_schedule_cache;
+pub mod leader_schedule_utils;
+pub mod perf_libs;
+pub mod poh;
+pub mod shred;
+pub mod staking_utils;