Convert search results to use PHUIObjectItemView

Summary: This moves global search results to use standard UI, and hopefully allow us to easily add more information.

Test Plan:
Tested a number of open and closed task queries, tried a few users and projects. All seem to work well.

Reviewers: btrahan, epriestley

Reviewed By: epriestley

Subscribers: Korvin, epriestley

Differential Revision: https://secure.phabricator.com/D11948