Organize blobs on disk by epoch (#14023)

* organize blob directories by period and epoch

* changelog

* remove Indices and replace with Summary

* old PR feedback

* log to advise about the speed of blob migration

* rename level->layer (hoping term is more clear)

* assert path in tests for increased legibility

* lint

* lint

* remove test covering a newly impossible error

* improve feedback from flag validation failure

* Try to clean dangling dirs epoch->flat migration

* lint

* Preston feedback

* try all layouts and short-circuit if base not found

---------

Co-authored-by: Kasey Kirkham <kasey@users.noreply.github.com>

beacon-chain/sync/initial-sync/service.go

@@ -292,13 +292,10 @@ func missingBlobRequest(blk blocks.ROBlock, store *filesystem.BlobStorage) (p2pt
 	if len(cmts) == 0 {
 		return nil, nil
 	}
-	onDisk, err := store.Indices(r, blk.Block().Slot())
-	if err != nil {
-		return nil, errors.Wrapf(err, "error checking existing blobs for checkpoint sync block root %#x", r)
-	}
+	onDisk := store.Summary(r)
 	req := make(p2ptypes.BlobSidecarsByRootReq, 0, len(cmts))
 	for i := range cmts {
-		if onDisk[i] {
+		if onDisk.HasIndex(uint64(i)) {
 			continue
 		}
 		req = append(req, &eth.BlobIdentifier{BlockRoot: r[:], Index: uint64(i)})