userguide: document flow_id, with examples - v2 #7885

Job	Run time
Prepare cbindgen	51s
Prepare dependencies	1m 4s
AlmaLinux 9	12m 45s
AlmaLinux 9 (no jansson)	1m 29s
AlmaLinux 9 Test Templates	10m 12s
AlmaLinux 8	10m 20s
Debian 10	7m 15s
Debian 11 (xdp)	13m 0s
Debian 12	30m 54s
Debian 12 Dist Builder	7m 37s
Debian 12 MSRV	25m 48s
Fedora 37 (clang, debug, asan, wshadow, rust-strict, systemd)	9m 30s
Fedora 37 (gcc, debug, asan, wshadow, rust-strict)	11m 31s
Fedora 37 (non-root, debug, clang, asan, wshadow, rust-strict, systemd)	7m 20s
Fedora 38 (clang, debug, asan, wshadow, rust-strict, systemd)	1h 19m 20s
Fedora 38 (gcc, debug, asan, wshadow, rust-strict)	8m 59s
Fedora 38 (Suricata Verify codecov)	11m 55s
MacOS Latest	25m 15s
Ubuntu 20.04 (-DNDEBUG)	13m 22s
Ubuntu 22.04 (fuzz corpus coverage)	15m 57s
Ubuntu 22.04 (unittests coverage)	10m 22s
Ubuntu 22.04 (Debug Validation)	13m 57s
Ubuntu 22.04 (DPDK Build) (22.11.3)	18m 4s
Ubuntu 22.04 (Fuzz)	13m 40s
Ubuntu 22.04 (DPDK Build) (21.11.5)	16m 0s
Ubuntu 22.04 (Netmap build)	3m 58s
Windows MSYS2 MINGW64 (libpcap)	28m 12s
Ubuntu 22.04 (DPDK Build) (20.11.9)	13m 22s
Windows MSYS2 MINGW64 (NPcap)	28m 43s
Ubuntu 22.04 (DPDK Build) (19.11.14)	13m 28s
Windows MSYS2 MINGW64 (WinDivert)	12m 45s
Ubuntu 20.04 (unsupported rust)	1m 19s
CentOS Stream 8	5m 58s
CentOS 7	21m 55s
CentOS Stream 9	5m 35s
	8h 31m 42s

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