Add more information to Dashboard ApplicationSearch list

Summary: Fixes T4984. This is about as fancy as I want to get this pass. Adds in the list of panel titles and the author. This does give me a rough idea what's on each dashboard.

Test Plan:
Visit a list of dashboards and see various authors and panels.

{F2810876}

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Maniphest Tasks: T4984

Differential Revision: https://secure.phabricator.com/D17340