userguide: remove old css files #8443

Job	Run time
Prepare dependencies	57s
Prepare cbindgen	14s
AlmaLinux 9	12m 25s
Fedora 38 (clang, debug, asan, wshadow, rust-strict, systemd)	56m 25s
Fedora 38 (Suricata Verify codecov)	7m 36s
AlmaLinux 9 (no jansson)	1m 4s
AlmaLinux 9 Test Templates	5m 22s
Debian 12	22m 22s
Debian 12 Dist Builder	4m 10s
Fedora 38 (gcc, debug, asan, wshadow, rust-strict)	8m 12s
Fedora 39 (non-root, debug, clang, asan, wshadow, rust-strict, systemd)	8m 19s
MacOS Latest	23m 4s
Windows MSYS2 MINGW64 (libpcap)	24m 34s
Windows MSYS2 MINGW64 (NPcap)	25m 22s
Windows MSYS2 MINGW64 (WinDivert)	12m 24s
Fedora 39 (clang, debug, asan, wshadow, rust-strict, systemd)	7m 48s
AlmaLinux 8	5m 50s
Fedora 39 (gcc, debug, asan, wshadow, rust-strict)	7m 57s
Debian 10	7m 22s
Debian 11 (xdp)	7m 23s
Debian 12 MSRV	21m 52s
Ubuntu 20.04 (-DNDEBUG)	9m 28s
Ubuntu 22.04 (fuzz corpus coverage)	12m 44s
Ubuntu 22.04 (unittests coverage)	6m 3s
Ubuntu 22.04 (Debug Validation)	9m 28s
Ubuntu 22.04 (DPDK Build) (22.11.3)	14m 39s
Ubuntu 22.04 (Fuzz)	6m 48s
Ubuntu 22.04 (DPDK Build) (21.11.5)	11m 48s
Ubuntu 22.04 (Netmap build)	3m 39s
Ubuntu 22.04 (DPDK Build) (20.11.9)	10m 24s
Ubuntu 22.04 (DPDK Build) (19.11.14)	9m 22s
CentOS Stream 9	6m 23s
CentOS 7	14m 5s
CentOS Stream 8	5m 38s
Ubuntu 20.04 (unsupported rust)	1m 11s
	6h 32m 22s

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