Paginate thread items

[sanderpick]

Dweb thread has about 60 photos in it... for whatever reason there's a big lag when I tap on it compares to other threads... I'd guess related to the underlying TextileImages. Seems like the OS or (React list component) does some intelligent loading of the items as you scroll, but probably not conservative enough.

Related, loading the list of thread items could be delayed until they are needed, doens't seem scalable as threads grow.

[andrewxhill]

We are now paging the loading of images. the entire thread history is loaded as json, but images are loaded one page at a time in the UI. i'm going to downgrade this from critical to just enhancement (to further page the request for thread history)