R1:2b21b4e88059

Add search app icon

Summary: It's an icon. For Search. Fixes T3966

Test Plan: Search

Reviewers: epriestley, btrahan

Reviewed By: epriestley

CC: Korvin, epriestley, aran

Maniphest Tasks: T3966

Differential Revision: https://secure.phabricator.com/D7389