refactor find many with many translations

They have to be created immediatly, cause they will be needed when the first translation needs to be created at the end of the `UnitOfWork::getOrCreateDocuments()`. When the Iterator works fine they will be fetched in a batch (with the config size) or all at once - as we like to have it.
That creation will hapen for `ChildTranslationStrategy` only.
Decided to do it that way cause creating a `createTranslations()` method to create all translations in a loop was horror. (tried it)