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

spec/services/fetch_link_card_service_spec.rb

@@ -0,0 +1,14 @@
+require 'rails_helper'
+
+RSpec.describe FetchLinkCardService do
+  before do
+    stub_request(:get, 'http://example.xn--fiqs8s/').to_return(request_fixture('idn.txt'))
+  end
+
+  it 'works with IDN URLs' do
+    status = Fabricate(:status, text: 'Check out http://example.中国')
+
+    FetchLinkCardService.new.call(status)
+    expect(a_request(:get, 'http://example.xn--fiqs8s/')).to have_been_made
+  end
+end