Fix number field search

Search with non numeric content will not hit number field (it breaks elasticsearch and is useless anyway)

- Rename QueryHelper::buildPrivateFieldQueries() to wrapPrivateFieldQuery().
    - Signature changed too, the third parameter is dropped an QueryContext is replaced by an array of Field.
    - Query builder closure is now passed an array of Field, not of index field names.
- Remove Field::toConceptPathIndexFieldArray() because method name was beyond understanding (and also because it wasn't needed anymore)
- Various AST node types have changed due to previous API changes

lib/Alchemy/Phrasea/SearchEngine/Elastic/Structure/Field.php

@@ -105,16 +105,6 @@ class Field
         );
     }
 
-    public static function toConceptPathIndexFieldArray(array $fields)
-    {
-        $index_fields = [];
-        foreach ($fields as $field) {
-            // TODO Skip fields without inference enabled?
-            $index_fields[] = $field->getConceptPathIndexField();
-        }
-        return $index_fields;
-    }
-
     public function getConceptPathIndexField()
     {
         return sprintf('concept_path.%s', $this->name);