Add a message for a 'Spam tools' group.

Add a message for a 'Spam tools' group.
Many extensions fall under this category, however there isn't a single one which would dominate this category.
It's best to localize this one inside of core to avoid multiple extensions trying to localize the same message, or worse, different id's with the same purpose. And ending up duplicating translations, with some lagging behind and potentially overriding newer translations in other extensions.