Optimize Notifications Rendering
It works like this:
- keeps count of how many seen notifications it should display per notifications column (we can have multiple thanks to interactions)
- increases the number when loading older to show more
- puts the number back to default whenever clicking "Read!", since we can be sure you're on top whenever you click it. This cuts off bloat in DOM from all the older notifications (which are still in store)
- when clicking load older while the older are still in store, it just increases the number to display, only fetching more when the number is greater than what's in store already.