Add new Suricata schema type 'packet'

[satta]

📔 Description

Add a new Suricata schema type 'packet'. this is output as EVE-JSON when the tagged-packets config option is set and a rule tags a packet using, e.g. tag:session,5,packets;. This PR adds schema support for this case, which has not been considered before.

📝 Checklist

• All user-facing changes have changelog entries.
• The changes are reflected on docs.tenzir.com/vast, if necessary.
• The PR description contains instructions for the reviewer, if necessary.

🎯 Review Instructions

Please test with current VAST version, I did not test (i.e. run the test suite) with the latest version due to compiler version issues.

[mavam]

Thanks for the contribution, I just tweaked the changelog entry a bit!