Modernize Slowvote Search

Summary: Updates slowvote search forms and results. Note I can't seem to get the Joins clause to fire anymore, is there a modern equiv?

Test Plan: Search on polls by state, votes, author, projects.

Reviewers: btrahan, epriestley

Reviewed By: epriestley

Subscribers: epriestley, Korvin

Differential Revision: https://secure.phabricator.com/D13666