Update JA4D implementation

[vlvkobal]

Following the new JA4D spec, this PR updates the DHCP fingerprint to include:

• message type character codes (e.g. reqst, offer, …),
• Requested IP (Opt 50) and FQDN (Opt 81) indicators for DHCPv4; IA_NA (Opt 3) and FQDN (Opt 39) indicators for DHCPv6,
• corrected item-length formatting and zero-padding.

New JA4D format example:

reqst1500in_61-57-60-12-55_1-3-6-15-26-28-51-58-59-43-114-108

[J0eJ0h]

I'm working on the Zeek version and the current spec wants 50 and 81 excluded from listed options as they are covered by the two characters in the first part.

[vlvkobal]

Thanks, @J0eJ0h - that slipped past me. Will fix it.