Remove AphrontMiniPanelView

Summary: Swaps out AphrontMiniPanelView usage with PHUIErrorView. Only used on homepage.

Test Plan:
Grepped for usage, only home. Revisit a new home, see modern componant.

Reviewers: btrahan, epriestley

Reviewed By: epriestley

Subscribers: Korvin, epriestley

Differential Revision: https://secure.phabricator.com/D11842