In permanent anonymous mode, data exports should allow associating sign-in data with opinions when anonymization_safe_opinion_filters is set

[tkriplean]

Apologies for the confusing title.

In data_exports.rb, user names and user emails are anonymized with:

        user_name = anonymize_permanently ?  'ANONYMOUS'  : user.name
        user_email = anonymize_permanently ?  'ANONYMOUS'  : user.email.gsub('.ghost', '')

However, if the anonymization_safe_opinion_filters customization is enabled, I'd like hosts to be able to associate the sign-in question data present in the users export sheet with the opinion and comment data. That way I could, say, analyze the opinions of people from a particular zipcode.

One way to do this is to create a unique pseudonym for each anonymous user, like "ANONYMOUS-4", instead of using a universal name like "ANONYMOUS".

cc: @chadbrower0