Refactoring to use PHUICalendarListView instead of boxes

Summary: Ref T4393, Refactoring to use PHUICalendarListView instead of boxes

Test Plan: See new sidebar

Reviewers: chad, Blessed Reviewers, epriestley

Reviewed By: Blessed Reviewers, epriestley

Subscribers: Korvin, epriestley

Maniphest Tasks: T4393

Differential Revision: https://secure.phabricator.com/D12743