Fix block backfill with genesis skip slots (#4820)

## Issue Addressed

Closes #4817.

## Proposed Changes

- Fill in the linear block roots array between 0 and the slot of the first block (e.g. slots 0 and 1 on Holesky).
- Backport the `--freezer`, `--skip` and `--limit` options for `lighthouse db inspect` from tree-states. This allows us to easily view the database corruption of 4817 using `lighthouse db inspect --network holesky --freezer --column bbr --output values --limit 2`.
- Backport the `iter_column_from` change and `MemoryStore` overhaul from tree-states. These are required to enable `lighthouse db inspect`.
- Rework `freezer_upper_limit` to allow state lookups for slots below the `state_lower_limit`. Currently state lookups will fail until state reconstruction completes entirely.

There is a new regression test for the main bug, but no test for the `freezer_upper_limit` fix because we don't currently support running state reconstruction partially (see #3026). This will be fixed once we merge `tree-states`! In lieu of an automated test, I've tested manually on a Holesky node while it was reconstructing.

## Additional Info

Users who backfilled Holesky to slot 0 (e.g. using `--reconstruct-historic-states`) need to either:

- Re-sync from genesis.
- Re-sync using checkpoint sync and the changes from this PR.

Due to the recency of the Holesky genesis, writing a custom pass to fix up broken databases (which would require its own thorough testing) was deemed unnecessary. This is the primary reason for this PR being marked `backwards-incompat`.

This will create few conflicts with Deneb, which I've already resolved on `tree-states-deneb` and will be happy to backport to Deneb once this PR is merged to unstable.

beacon_node/store/src/hot_cold_store.rs

@@ -1490,10 +1490,17 @@ impl<E: EthSpec, Hot: ItemStore<E>, Cold: ItemStore<E>> HotColdDB<E, Hot, Cold>
         let split_slot = self.get_split_slot();
         let anchor = self.get_anchor_info();
 
-        // There are no restore points stored if the state upper limit lies in the hot database.
-        // It hasn't been reached yet, and may never be.
-        if anchor.map_or(false, |a| a.state_upper_limit >= split_slot) {
+        // There are no restore points stored if the state upper limit lies in the hot database,
+        // and the lower limit is zero. It hasn't been reached yet, and may never be.
+        if anchor.as_ref().map_or(false, |a| {
+            a.state_upper_limit >= split_slot && a.state_lower_limit == 0
+        }) {
             None
+        } else if let Some(lower_limit) = anchor
+            .map(|a| a.state_lower_limit)
+            .filter(|limit| *limit > 0)
+        {
+            Some(lower_limit)
         } else {
             Some(
                 (split_slot - 1) / self.config.slots_per_restore_point