Add polls (#10111)

* Add polls

Fix #1629

* Add tests

* Fixes

* Change API for creating polls

* Use name instead of content for votes

* Remove poll validation for remote polls

* Add polls to public pages

* When updating the poll, update options just in case they were changed

* Fix public pages showing both poll and other media

spec/models/poll_spec.rb

@@ -0,0 +1,5 @@
+require 'rails_helper'
+
+RSpec.describe Poll, type: :model do
+  pending "add some examples to (or delete) #{__FILE__}"
+end