* Backend changes for custom emoji support in poll options

* Serialize poll emojis in REST API

* Render custom emojis in poll options

* Render custom emoji in poll options on public pages

* Add UI for enabling/disabling poll notifications

* Add poll notifications to the (advanced) quick filter bar

* Update poll notification message

“Your poll has ended” → “A poll you have voted in has ended”

* Clear up associated notifications when a poll is deleted

* Do not allow adding votes to expired polls

* Only validate expires_at on create

* Immediately display poll results to poll author

* Refactor Poll#loaded_options and add Poll#voted? to improve DRYness

* Add optimistic lock to avoid race conditions when handling votes

* Force-reload polls when getting `ActiveRecord::StaleObjectError`

* 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