Add a basic icon typeahead
Summary: Fixes T11971, adds a basic typeahead for selecting an icon.
Test Plan:
http://local.phacility.com/typeahead/browse/PhabricatorIconDatasource/
{F2561013}
Reviewers: epriestley
Reviewed By: epriestley
Subscribers: Korvin
Maniphest Tasks: T11971
Differential Revision: https://secure.phabricator.com/D17301