Add "nofollow noopener noreferrer" to all links (#698)

Old iOS 12 devices will pass the Referer HTTP header to the site user clicks.
Websites will know those traffic come from Whoogle search.
Adding "nofollow noopener noreferrer" solves the issue.

app/utils/search.py

@@ -153,6 +153,7 @@ class Search:
                                 self.request_params.to_dict(flat=True).items()
                                 if self.config.is_safe_key(k))
             for link in formatted_results.find_all('a', href=True):
+                link['rel'] = "nofollow noopener noreferrer"
                 if 'search?' not in link['href'] or link['href'].index(
                         'search?') > 1:
                     continue