R1:6bb24e1d0cbd

Move PhabricatorHovercard to PHUIHovercard

Summary: No UI changes, just some search and replace for UI consistency.

Test Plan: Test person and object hovercards still work. UIExamples too.

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Differential Revision: https://secure.phabricator.com/D15172