Store changes to persist data columns (#6073)

* Store changes to persist data columns.

Co-authored-by: dapplion <35266934+dapplion@users.noreply.github.com>

* Update to use `eip7594_fork_epoch` for data column slot in Store.

* Fix formatting.

* Merge branch 'unstable' into data-columns-store

# Conflicts:
#	beacon_node/store/src/lib.rs
#	consensus/types/src/chain_spec.rs

* Minor refactor.

* Merge branch 'unstable' into data-columns-store

# Conflicts:
#	beacon_node/store/src/metrics.rs

* Init data colum info at PeerDAS epoch instead of Deneb fork epoch. Address review comments.

* Remove Deneb-related comments

beacon_node/store/src/memory_store.rs

@@ -1,6 +1,6 @@
 use crate::{
     get_key_for_col, leveldb_store::BytesKey, ColumnIter, ColumnKeyIter, DBColumn, Error,
-    ItemStore, Key, KeyValueStore, KeyValueStoreOp,
+    ItemStore, Key, KeyValueStore, KeyValueStoreOp, RawKeyIter,
 };
 use parking_lot::{Mutex, MutexGuard, RwLock};
 use std::collections::BTreeMap;
@@ -100,6 +100,18 @@ impl<E: EthSpec> KeyValueStore<E> for MemoryStore<E> {
         }))
     }
 
+    fn iter_raw_keys(&self, column: DBColumn, prefix: &[u8]) -> RawKeyIter {
+        let start_key = BytesKey::from_vec(get_key_for_col(column.as_str(), prefix));
+        let keys = self
+            .db
+            .read()
+            .range(start_key.clone()..)
+            .take_while(|(k, _)| k.starts_with(&start_key))
+            .filter_map(|(k, _)| k.remove_column_variable(column).map(|k| k.to_vec()))
+            .collect::<Vec<_>>();
+        Box::new(keys.into_iter().map(Ok))
+    }
+
     fn iter_column_keys<K: Key>(&self, column: DBColumn) -> ColumnKeyIter<K> {
         Box::new(self.iter_column(column).map(|res| res.map(|(k, _)| k)))
     }