Punycode URI normalization (#2370)

* Fix #2119 - Whenever about to send a HTTP request, normalize the URI

* Add test for IDN request in FetchLinkCardService

* Perform IDN normalization on domains before they are stored in the DB

app/validators/url_validator.rb

@@ -8,7 +8,7 @@ class UrlValidator < ActiveModel::EachValidator
   private
 
   def compliant?(url)
-    parsed_url = Addressable::URI.parse(url)
+    parsed_url = Addressable::URI.parse(url).normalize
     !parsed_url.nil? && %w(http https).include?(parsed_url.scheme) && parsed_url.host
   end
 end