Add recursive option to `ipfs files ls`

Having a "recursive" option for ipfs files ls would be pretty handy for "finding" data.

I encountered corrupt CID's in #8103.
The corrupted CID's were identified via ```ipfs repo verify```, and I can list the CID's one folder at a time via ```ipfs files ls -l /```, however I have to go directory-by-directory to list them all.

Ideally, ```ipfs files ls -r -l /``` would exist so I can dump all the files in MFS, and grep for the CID.