[Redesign] PhabricatorApplicationSearchResultView

Summary: Ref T8099. This adds a new class which all search engines return for layout. I thought about this a number of ways, and I think this is the cleanest path. Each Engine can return whatever UI bits they needs, and AppSearch or Dashboard picks and lays the bits out as needed. In the AppSearch case, interfaces like Notifications, Calendar, Legalpad all need more custom layouts. I think this also leaves a resonable path forward for NUX as well. Also, not sure I implemented the class correctly, but assume thats easy to fix?

Test Plan: Review and do a search in each application changed. Grep for all call sites.

Reviewers: btrahan, epriestley

Reviewed By: epriestley

Subscribers: epriestley, Korvin

Maniphest Tasks: T8099

Differential Revision: https://secure.phabricator.com/D13332