Add missing ADDITIVES_TAGS_IN_LANGUAGES and ALLERGENS_TAGS_IN_LANGUAGES

[goerlitz]

Why - Problem description

Currently, it is not possible to execute following API request because in ProductField the required
ADDITIVES_TAGS_IN_LANGUAGES and ALLERGENS_TAGS_IN_LANGUAGES field definitions are missing.

https://de.openfoodfacts.org/api/v2/product/20101268?fields=additives_tags_de,additives_tags_en,allergens_tags_de,allergens_tags_en

Moreover, the existing ADDITIVES(offTag: 'additives_tags') and ALLERGENS(offTag: 'allergens_tags') do not follow the existing naming convention - they should be named ADDITIVES_TAGS and ALLERGENS_TAGS.

What - Proposed solution

Add ADDITIVES_TAGS_IN_LANGUAGES and ALLERGENS_TAGS_IN_LANGUAGES and the logic to handle these fields properly.

[goerlitz]

@monsieurtanuki I just implemented the feature. Would be great if you can have a look.

[monsieurtanuki]

Fixed in #929.