Infinite post feed scroll

[kgilles]

Today's big social media platforms have users expecting that they should (almost)never reach the end of a feed while scrolling. Nor have to take any action to see more posts/videos/etc in the feed. We want to follow that standard and enable infinite scrolling in our post feeds for the main instance pages and community pages.

Acceptance Criteria

• When a user reaches the bottom of the currently loaded posts in a feed, fetch and render the next 20(or so) posts automatically
• As post feed sorting can change in real-time based on votes, there may be a chance that the same post appears multiple times when new posts are continuously fetched. In these scenarios, hide all duplicates.