Improve Audit tool filters

Summary: Add more filters/options to the /audit/ interface (By User, By Package,
By Project...)

Test Plan: Looked at audits via /audit/.

Reviewers: btrahan, jungejason

Reviewed By: jungejason

CC: aran, epriestley

Maniphest Tasks: T904

Differential Revision: https://secure.phabricator.com/D1705