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