Filter exports based on common blocklists

[janheinrichmerker]

To make the exports more safe, we should block known phishing sites etc.
Michael and Sebastian have pointed me to these blocklists as used by the OWS crawling:

• https://github.com/Ultimate-Hosts-Blacklist/Ultimate.Hosts.Blacklist
• https://github.com/Phishing-Database/Phishing.Database
• https://dsi.ut-capitole.fr/blacklists/index_en.php