fix: tcpassembly does not use correct timestamps

[xhantu]

tcpassembly only read the bytes of the reassembled stream and ignored other reassembly information, like seen timestamp. Therefore When assembling a HEP packet it had to use the current time. Because of parallel handling of packet capture, reassembly, and extraction this timestamp could be totally wrong.

The changed code processes the reassembly information directly and uses the timestamp of the part with the begin of the SIP message.

refs: https://github.com/sipcapture/heplify/issues/223

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[lmangani]

GREAT contribution! Thanks @xhantu 🎉

[xhantu]

I did not set an email when committing. How do I sign the CLA now that I can not add the email to my account?

[lmangani]

Error: decoder/tcpassembly.go:12:2: "github.com/negbie/logp" imported and not used