Use the same serializer for all contact related actions

Also, rerun the response with an RFC4627 formatter

test/lib/serializers/registrant_api/contact_test.rb

@@ -0,0 +1,26 @@
+require 'test_helper'
+require 'serializers/registrant_api/contact'
+
+class SerializersRegistrantApiContactTest < ActiveSupport::TestCase
+  def setup
+    @contact = contacts(:william)
+    @serializer = Serializers::RegistrantApi::Contact.new(@contact)
+    @json = @serializer.to_json
+  end
+
+  def test_returns_uuid_as_id
+    assert_equal(@contact.uuid, @json[:id])
+  end
+
+  def test_returns_indent_as_separate_object
+    expected_ident = { code: @contact.ident, type: @contact.ident_type,
+                        country_code: @contact.ident_country_code }
+    assert_equal(expected_ident, @json[:ident])
+  end
+
+  def test_returns_address_as_separate_object
+    expected_address = { street: @contact.street, zip: @contact.zip, city: @contact.city,
+                         state: @contact.state, country_code: @contact.country_code }
+    assert_equal(expected_address, @json[:address])
+  end
+end