Add all read-only compatible zpool features to grub2 compatibility

GRUB opens the boot pool in read-only mode. All read-only
compatible features for zpool can be enabled and added to
grub2 compatibility, as GRUB does not open the boot-pool
for write.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Umer Saleem <usaleem@ixsystems.com>
Closes #15459

cmd/zpool/compatibility.d/grub2

@@ -1,6 +1,9 @@
 # Features which are supported by GRUB2
+allocation_classes
 async_destroy
+block_cloning
 bookmarks
+device_rebuild
 embedded_data
 empty_bpobj
 enabled_txg
@@ -9,6 +12,13 @@ filesystem_limits
 hole_birth
 large_blocks
 livelist
+log_spacemap
 lz4_compress
+obsolete_counts
+project_quota
+resilver_defer
 spacemap_histogram
+spacemap_v2
+userobj_accounting
+zilsaxattr
 zpool_checkpoint