ActivityPub::ProcessPollService was checking the JSON-LD context although
it was passed only the `Question` object embedded in the `Update` activity.

* Process incoming poll tallies update

* Send Update on poll vote

* Do not send Updates for a poll more often than once every 3 minutes

* Include voters in people to notify of results update

* Schedule closing poll worker on poll creation

* Add new notification type for ending polls

* Add front-end support for ended poll notifications

* Fix UpdatePollSerializer

* Fix Updates not being triggered by local votes

* Fix tests failure

* Fix web push notifications for closing polls

* Minor cleanup

* Notify voters of both remote and local polls when those close

* Fix delivery of poll updates to mentioned accounts and voters

* Make sure the poll is created before storing its id

* Fix updating poll results

* Support fetching Question activities from the search bar

* 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