Set event policies like other event properties
Summary: Closes T8028, Set event policies like other event properties
Test Plan: Create and edit events, make sure edit and view policies get populated and saved correctly.
Reviewers: epriestley, Blessed Reviewers
Reviewed By: epriestley, Blessed Reviewers
Subscribers: epriestley, Korvin
Maniphest Tasks: T8028
Differential Revision: https://secure.phabricator.com/D13415