Backfill data columns (#15580)

**What type of PR is this?**

Feature

**What does this PR do? Why is it needed?**

Adds data column support to backfill.

**Acknowledgements**

- [x] I have read
[CONTRIBUTING.md](https://github.com/prysmaticlabs/prysm/blob/develop/CONTRIBUTING.md).
- [x] I have included a uniquely named [changelog fragment
file](https://github.com/prysmaticlabs/prysm/blob/develop/CONTRIBUTING.md#maintaining-changelogmd).
- [x] I have added a description to this PR with sufficient context for
reviewers to understand this PR.

---------

Co-authored-by: Kasey <kasey@users.noreply.github.com>
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: Preston Van Loon <preston@pvl.dev>

cmd/beacon-chain/das/flags/BUILD.bazel

@@ -0,0 +1,12 @@
+load("@prysm//tools/go:def.bzl", "go_library")
+
+go_library(
+    name = "go_default_library",
+    srcs = ["flags.go"],
+    importpath = "github.com/OffchainLabs/prysm/v7/cmd/beacon-chain/das/flags",
+    visibility = ["//visibility:public"],
+    deps = [
+        "//config/params:go_default_library",
+        "@com_github_urfave_cli_v2//:go_default_library",
+    ],
+)

cmd/beacon-chain/das/flags/flags.go

@@ -0,0 +1,25 @@
+package flags
+
+import (
+	"github.com/OffchainLabs/prysm/v7/config/params"
+	"github.com/urfave/cli/v2"
+)
+
+var (
+	BackfillOldestSlot = &cli.Uint64Flag{
+		Name: "backfill-oldest-slot",
+		Usage: "Specifies the oldest slot that backfill should download. " +
+			"If this value is greater than current_slot - MIN_EPOCHS_FOR_BLOCK_REQUESTS, it will be ignored with a warning log.",
+	}
+	BlobRetentionEpochFlag = &cli.Uint64Flag{
+		Name:    "blob-retention-epochs",
+		Usage:   "Override the default blob retention period (measured in epochs). The node will exit with an error at startup if the value is less than the default of 4096 epochs.",
+		Value:   uint64(params.BeaconConfig().MinEpochsForBlobsSidecarsRequest),
+		Aliases: []string{"extend-blob-retention-epoch"},
+	}
+)
+
+var Flags = []cli.Flag{
+	BackfillOldestSlot,
+	BlobRetentionEpochFlag,
+}