Show pending audits on home page

Summary: When a user has pending audits, show them on the homepage.

Test Plan: Looked at my homepage with and without pending audits.

Reviewers: btrahan, jungejason

Reviewed By: jungejason

CC: aran, epriestley

Maniphest Tasks: T904

Differential Revision: https://secure.phabricator.com/D1692