feat: ls incomplete DAG

[alanshaw]

In the case where your DAG is complete, there should be no change to the output. However if your DAG is incomplete it'll try it's hardest to list the UnixFS data, flagging where blocks are missing.

e.g.

CAR with a directory block but does not have any leaves:

$ ipfs-car ls my.car 
.
./Upload at 2023-11-27T04:56:54.604Z    (missing)
./Upload at 2023-11-25T05:56:24.116Z    (missing)
./Upload at 2023-11-25T10:05:44.545Z    (missing)
./Upload at 2023-11-26T07:42:42.200Z    (missing)
./Upload at 2023-11-27T08:39:24.881Z    (missing)
./Upload at 2023-11-28T18:33:01.110Z    (missing)

$ ipfs-car ls my.car --verbose
bafybeiflihnr6z4slbbctflgvce3f6kniaemnoxhertujqvf3hyij5sjhi     -       .
bafkreigmm7bykylymj6qpov2w7l7af7l2jc7ooqv66c7gcm3ee2cmi4jse     ?       ./Upload at 2023-11-27T04:56:54.604Z    (missing)
bafkreif4bad34bxkka52oiubyt3rnpufamlv43v5kajiqn4bsjphcoefzq     ?       ./Upload at 2023-11-25T05:56:24.116Z    (missing)
bafkreigxob62zd6iyzz5uv63ni2vd55nty5ouhar5lr5f2gvzg4pbweod4     ?       ./Upload at 2023-11-25T10:05:44.545Z    (missing)
bafkreianpm6royd6sykexq6pj2j73muemozsyazjhwfq6ypzu7himwnqti     ?       ./Upload at 2023-11-26T07:42:42.200Z    (missing)
bafkreihx3oqgdibv4apw63w64usg3vj2uk2zuiv6oov3nfpeax4nw6h4pu     ?       ./Upload at 2023-11-27T08:39:24.881Z    (missing)
bafkreiezq3rgts3ytajd7vf6sagmjnqxzmp2lnvsyvmbrflq5wmrzicngm     ?       ./Upload at 2023-11-28T18:33:01.110Z    (missing)