Allow ordering of badges by quality

Summary: Ref T9007

Test Plan: Navigate to "Advanced Search" in Badges, order by rarity, then by commonality. Rarest and most common badges should be ordered, respectively.

Reviewers: #blessed_reviewers, epriestley

Reviewed By: #blessed_reviewers, epriestley

Subscribers: Korvin

Maniphest Tasks: T9007

Differential Revision: https://secure.phabricator.com/D15555