Lots of new code for importer and some preferences.

app/Import/Converter/ConverterInterface.php

@@ -31,6 +31,11 @@ interface ConverterInterface
      */
     public function setConfig(array $config);
 
+    /**
+     * @return int
+     */
+    public function getCertainty(): int;
+
     /**
      * @param bool $doMap
      */