Add the option for exact search against product_name

[teolemon]

Add the option for exact search against product_name. It will be useful for data maintenance queries such as all products with "6 œufs frais" as a name, but without without a category.

https://fr.openfoodfacts.org/cgi/search.pl?action=process&sort_by=unique_scans_n&page_size=20&action=display&tagtype_0=states&tag_contains_0=contains&tag_0=categories%20to%20be%20completed&search_terms=6%20%C5%93ufs%20bio

[wiki-me]

I think this is the default for every calorie tracking app i enoutered (myfitnesspal,cronometer, Fatsecret , lose it , nutritionvalue).

When this is not the default search becomes unusable (atleast when searching for something like "egg").

[github-actions[bot]]

This issue has been open 90 days with no activity. Can you give it a little love by linking it to a parent issue, adding relevant labels and projets, creating a mockup if applicable, adding code pointers from https://github.com/openfoodfacts/openfoodfacts-server/blob/main/.github/labeler.yml, giving it a priority, editing the original issue to have a more comprehensive description… Thank you very much for your contribution to 🍊 Open Food Facts