…nto mpenny_noble_build

Make 'script/cibuild-create-packages focal' and
'script/cibuild-create-packages noble' both succeed by adding
compatibility shims for DPDK 23.11 (Noble) while keeping the existing
DPDK 17.11 (Focal) build working.

Build system:
- src/glb-director/Makefile: detect the legacy DPDK make fragments;
  when absent (Noble), fall back to a pkg-config based build that
  produces build/app/glb-director.
- src/glb-redirect/Makefile: detect /etc/dkms/template-dkms-mkdeb at
  runtime. On Focal use the legacy 'dkms mkdeb --source-only' path.
  On Noble dispatch to a new mkdeb-dh-dkms target that synthesises a
  minimal debian/ tree (control, changelog, rules, source/format,
  .dkms, .install) and runs dpkg-buildpackage with dh-dkms, producing
  the same glb-redirect-iptables-dkms_<ver>_all.deb artifact.
- script/Dockerfile.noble: add dh-dkms, dpkg-dev, and fakeroot for the
  modern packaging path.

DPDK 23.11 source compatibility:
- main.c: gate <rte_kni.h> with __has_include; switch
  rte_eth_dev_count() to GLB_ETH_DEV_COUNT(); guard pre-22.11 rxmode
  fields (header_split / hw_ip_checksum / hw_vlan_filter /
  jumbo_frame / hw_strip_crc) with RTE_VERSION; define and register
  glb_mbuf_userdata_offset when GLB_HAVE_MBUF_USERDATA_DYNFIELD is set.
- glb_kni.c: gate the whole file on GLB_HAVE_KNI (KNI was removed in
  DPDK 23.11) and provide no-op stubs for the public glb_kni_* API in
  the disabled branch.
- bind_classifier.c: include config.h before bind_classifier_rules.h
  so the ipv4_hdr/ipv6_hdr -> rte_* aliases are visible to the rule
  table definitions.
- cmdline_parse.c: introduce CMDLINE_CTX() macro to use
  cmdline_get_ctx() on DPDK >= 22.11 (struct cmdline became opaque).

C hygiene fixes surfaced by newer toolchain:
- log.h: add include guard and change 'bool debug;' to extern; the
  single definition now lives in shared_opt.c. Fixes multiple-
  definition link errors on newer GCC defaults (-fno-common).
- strlcpy.h: add header guard to prevent the static inline strlcpy
  from being declared twice when included via multiple paths.

Both 'script/cibuild-create-packages focal' and
'script/cibuild-create-packages noble' now exit 0 and produce the
expected .deb artifacts (glb-director-cli, glb-director, glb-director-
xdp, xdp-root-shim, glb-healthcheck, glb-redirect-iptables-dkms).