Updates to phrequent's landing page

Summary:
https://secure.phabricator.com/D5554#comment-4

Implemented the changes outlined above.

Test Plan: Go to the page, click the new nav links, try the user filter

Reviewers: epriestley, hach-que

CC: hach-que, aran, Korvin

Differential Revision: https://secure.phabricator.com/D5789