Move blocktree_processor to solana_ledger (#6460)

* Drop core::result dependency in bank_forks

* Move blocktree_processor into solana_ledger

ledger-tool/tests/basic.rs

@@ -2,8 +2,8 @@
 extern crate solana_ledger;
 
 use assert_cmd::prelude::*;
-use solana_core::genesis_utils::create_genesis_block;
 use solana_ledger::blocktree::create_new_tmp_ledger;
+use solana_ledger::genesis_utils::create_genesis_block;
 use std::process::Command;
 use std::process::Output;