Add last git hash from application build time

src/bin/satcmd.skel

 SATURNIN_APP_CODENAME="__MKIT_PROJ_CODENAME__"
 SATURNIN_APP_TAGLINE="__MKIT_PROJ_TAGLINE__"
 SATURNIN_APP_VERSION="__MKIT_PROJ_VERSION__"
+SATURNIN_APP_GIT_HASH="__MKIT_PROJ_GIT_LASTHASH__"
 SATURNIN_CACHE_HOME="__SATURNIN_CACHE_HOME__"
 SATURNIN_LIBEXEC="__SATURNIN_LIBEXEC__"
 SATURNIN_LIBEXEC_PREFIX="__MKIT_PROJ_PKGNAME__-"

src/shellfu/saturnin.sh

     case "$key" in
         shellfu-path)   echo "$SHELLFU_PATH"                ;;
         inigrep-path)   echo "$SHELLFU_INIGREP_PATH"        ;;
+        app-git-hash)   echo "$SATURNIN_APP_GIT_HASH"       ;;
         app-version)    echo "$SATURNIN_APP_VERSION"        ;;
         cache-home)     echo "$SATURNIN_CACHE_HOME"         ;;
         libexec)        echo "$SATURNIN_LIBEXEC"            ;;