WIP getting user activity to page properly
Another pagination/list handling overhaul...

 - Attempting to combine paging/offset for bounded and unbounded
   lists (search results, activity streams) did not work well on
   the backend since it broke the ability to fetch "one more" than
   the needed number of a stream to check if there was any more
   content.
 - Introduced RangeParams handler to deal with this for unbounded
   streams. PageParams converts page into offset for the backend,
   RangeParams uses the offset directly.
Add new infitite-pageable user activity list.
Cleanup how pagination namespacing is handled in templates