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

app/javascript/styles/application.scss

@@ -16,6 +16,7 @@
 @import 'mastodon/stream_entries';
 @import 'mastodon/boost';
 @import 'mastodon/components';
+@import 'mastodon/polls';
 @import 'mastodon/introduction';
 @import 'mastodon/modal';
 @import 'mastodon/emoji_picker';