Updated bounty page using pages/bounties/index.tsx and newly, compone…

[TylerDiorio]

Updated the Bounties page using feedback from RHF (including all sidebar copy). Now using a components/Bounty/BountyFeedCard.tsx.

Few lignering issues that need to be fixed, @yattias I could use some help processing the bounties here but the feed is working otherwise:

1. Trouble parsing the bounty data for Hubs - right now, Hubs are not displaying in the BountyFeedCard.tsx because they aren't identified.
2. Trouble parsing the bounty data for the type of bounty (Peer Review, answer to a question, other) as denoted by the bountyTypeLabel[bountyType].
3. First author will populate as user who posted the paper sometimes, but not always, which makes it difficult to scrub when surfacing the authors of the target paper.