Pull request #4465: tcp_pdu: new inspector for simple length based flushing

Pull request #4465: tcp_pdu: new inspector for simple length based flushing

Merge in SNORT/snort3 from ~RUCOMBS/snort3:tcp_pdu to master

Squashed commit of the following:

commit 58b1bc69c07c863d04c446207eb317d99ed1e7fd
Author: Russ Combs <rucombs@cisco.com>
Date:   Mon Sep 16 14:06:01 2024 -0400

    tcp_pdu: new inspector for simple length based flushing

    tcp_pdu provides a generic protocol-aware-flushing capability for PDUs
    that contain a length field. The field may be at a configurable offset
    from the start of the PDU, it has a configurable length, and may specify
    the total length of the PDU or the number of bytes following the length
    field.