Add example command satcmd-dump

Useful for testing saturnin itself

mkit.ini

     src/complete.bash           = satcmd.bash
 
 [files:libexec]
+    src/libexec/satcmd-dump     = satcmd-dump
     src/libexec/satcmd-echo     = satcmd-echo
 
 [files:share]

packaging/satcmd.spec

 %dir /usr/local/share/satcmd/shellfu
 %doc /usr/local/share/doc/satcmd/README.md
 /usr/local/bin/satcmd
+/usr/local/libexec/satcmd/satcmd-dump
 /usr/local/libexec/satcmd/satcmd-echo
 /usr/local/share/satcmd/ini.d/main/echo.ini
 /usr/local/share/satcmd/shellfu/saturnin.sh

src/libexec/satcmd-dump

+#!/bin/bash
+
+. "$(shellfu-get path)" || exit 3
+
+env | sort | xargs -L 1 satcmd echo