Add more NUX states

Summary: Adds basic NUX to Dashboards, Herald, Repositories, Maniphest. Note Herald and Dashboard Panels don't fine the nux for some reason, assume they will when modernized?

Test Plan: Read text, click buttons.

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Differential Revision: https://secure.phabricator.com/D14844