R1:8ade91486cfc

Add `calendar.event.search` and `calendar.event.edit`

Summary: Ref T7944. The search method is a bit bare-bones for now, but these substantially work.

Test Plan: Edited events via API; queried events via API.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T7944

Differential Revision: https://secure.phabricator.com/D16288