Use blueprint filesystem customizations to create partitions

This also allows the root filesystem size to be increased if the default
of 10GiB isn't enough.

bib/cmd/bootc-image-builder/image.go

@@ -145,7 +145,12 @@ func pipelinesForDiskImage(c *ManifestConfig, rng *rand.Rand) (image.ImageKind,
 	if !ok {
 		fail(fmt.Sprintf("pipelines: no partition tables defined for %s", c.Architecture))
 	}
-	pt, err := disk.NewPartitionTable(&basept, nil, DEFAULT_SIZE, disk.RawPartitioningMode, nil, rng)
+	pt, err := disk.NewPartitionTable(&basept,
+		customizations.GetFilesystems(),
+		DEFAULT_SIZE,
+		disk.RawPartitioningMode,
+		nil,
+		rng)
 	check(err)
 	img.PartitionTable = pt