SMB: optional legacy mode (SMB1 + NTLMv1) for old clients

Supermicro BMC virtual media ("CD-ROM image" over a Windows share) only
offers the SMB1 dialect "NT LM 0.12", which Samba rejects with
server min protocol = SMB2. Add an opt-in "Allow legacy clients" SMB
setting that renders server min protocol = NT1 and
ntlm auth = ntlmv1-permitted. Off by default.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

packaging/README.md

@@ -36,7 +36,9 @@ also after resolving symlinks. Definitions are stored in
 /etc/samba/smb.conf (whole file, header "Managed by nasmon") and
 /etc/exports.d/nasmon.exports, validates with testparm, then reloads smbd /
 exportfs -ra. A rejected config is rolled back to the .bak copy. Daemons are
-enabled while at least one share exists and disabled otherwise.
+enabled while at least one share exists and disabled otherwise. "Allow legacy
+clients" in the SMB settings turns on SMB1 + NTLMv1 (server min protocol = NT1)
+for IPMI/BMC virtual media and other old devices; it is off by default.
 
 Alerts: the × on an open alert acknowledges it (hidden and not mailed until the
 problem changes or clears); the × on a resolved alert removes it from the log.