Drop GIMP workload; make Inkscape export a tunable subset

GIMP 3 removed/renamed the Script-Fu PDB calls the workload relied on
(plug-in-unsharp-mask, gimp-levels-stretch), so it is removed rather than
maintained as best-effort. Inkscape now exports the first INKSCAPE_FILES SVGs
(default 25) instead of all 121, cutting that step to well under a minute.

capture-specs.sh

@@ -54,7 +54,7 @@ disks() {
 tool_versions() {
   for c in 7z openssl fio stress-ng sysbench sensors turbostat cpupower \
            glmark2 vkmark glxinfo vulkaninfo python3 \
-           libreoffice inkscape gegl gimp; do
+           libreoffice inkscape gegl; do
     have "$c" && printf '    %-20s %s\n' "$c" "$("$c" --version 2>&1 | head -1)"
   done
   local pt="$DIR/tools/pt/PerformanceTest/PerformanceTest_Linux_x86-64"