Improve database compaction and prune-states (#5142)

* Fix no-op state prune check

* Compact freezer DB after pruning

* Refine DB compaction

* Add blobs-db options to inspect/compact

* Better key size

* Fix compaction end key

beacon_node/store/src/hot_cold_store.rs

@@ -2376,6 +2376,9 @@ impl<E: EthSpec, Hot: ItemStore<E>, Cold: ItemStore<E>> HotColdDB<E, Hot, Cold>
             self.cold_db.do_atomically(cold_ops)?;
         }
 
+        // In order to reclaim space, we need to compact the freezer DB as well.
+        self.cold_db.compact()?;
+
         Ok(())
     }
 }