Hook up the Settings page

Summary:
- underscore.js
- useful ignores for ack users (will stack with your ~/.ackrc)
- add Util service
- combine constants
- improve module formatting
- add gulp-notify
- consolidate config endpoints
- hook up config form

Test Plan: try out the settings page (and other pages), run the tests

Reviewers: seth, rjmackay, vladimir, shadowhand

Reviewed By: shadowhand

Maniphest Tasks: T1065

Differential Revision: https://phabricator.ushahidi.com/D522