Implement an extremely primitive typeahead browse view with offset paging

Summary:
Ref T5750. Give up and use offset paging.

Each page will become progressively slower, but the amount of time I was sinking into T7803 without making real headway was not justified by fixing this. In comparison, this took 10 minutes. It isn't really useful to browse through tens of thousands of results anyway, and no one is realistically going to try to do that (later in this sequence, I'll explicitly prevent it).

Test Plan:
This is completely primitive right now:

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T5750

Differential Revision: https://secure.phabricator.com/D12423