epm tool: add which command

bin/epm-tool

@@ -62,6 +62,9 @@ epm_tool()
             showcmd json "$@"
             $SHAREDIR/tools_json "$@"
             ;;
+        "which")
+            print_command_path "$@"  # HELPCMD: which like command (no output to stderr, can works without which package)
+            ;;
         *)
             fatal "Unknown command $ epm tool $WHAT. Use epm print help for get help."
             ;;