A rough start for ksmbd

In the absence of kerberos, the server's mostly just trusting the clients to correctly represent who's accessing the filesystem anyway.

I seem to recall one or two people making an attempt at adding this kind of mapping, and it turning out to be more complicated than expected. But that was a while ago. I wonder if any of the container work done since then would be useful here.

Anyway, there'd have to be someone willing to look into it and do the work.