"append" (true|false) for map & object

[clemzarch]

        - fastmap:
            expression_language:
              - Kiboko\Component\ArrayExpressionLanguage\ArrayExpressionLanguageProvider
+            append: true
            map:
               # ...

- $output = (function ($input) {
+ $output = (function ($input) use($output) {
-    $output = [];
    $output['sku'] = (function () use($input) {
        ....
    })();
    return $output;
})($input);
return $output;