* Compute answer group feed items
* Refactor feed code into 5 files under feed directory.
* Convert to typed ActivityItems
* Use feed "mode". Clean up cases.
* Implement feed answer groups!
* FR: Use nested comments/bets under answers for contract page. filter more items out of FR feed.
* Linkify answer text on activity feed
* Default feed excluded tags are case insensitive
* Show followed folds first
* Allow filtering your trades
* Store users's last sort in localstorage
* Use avatar of user that submitted answer and name instead of pencil icon. Spacing. Show up to 3 comments in asnwer group.
* Don't reveal market creator's bets
* Fix communites feed to be abbreviated
* Remove complicated answer group logic
Co-authored-by: Austin Chen <akrolsmir@gmail.com>
