refactor: split reth-stages into reth-stages-api and reth-stages (#7666)

Co-authored-by: Oliver Nordbjerg <hi@notbjerg.me>

bin/reth/src/commands/import.rs

@@ -34,6 +34,7 @@ use reth_provider::{HeaderSyncMode, ProviderFactory, StageCheckpointReader};
 use reth_stages::{
     prelude::*,
     stages::{ExecutionStage, ExecutionStageThresholds, SenderRecoveryStage},
+    Pipeline, StageSet,
 };
 use reth_static_file::StaticFileProducer;
 use std::{path::PathBuf, sync::Arc};