iredapd / TODO

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* rename variables: ldapSenderLdif -> sender_ldif or ldif_of_sender
* plugin/ set password last update date to today if
  shadowLastChange is not present or 0?
* Query required SQL columns instead of all
* Plugins:
    + HELO restrictions
    + Greylisting (server-wide and per-user, per-domain)
    + White/Blacklisting (server-wide and per-domain)
    + Require STARTTLS (encryption_protocol=TLSv1)
* Detect protocol_state=RCPT in smtp session