Add Indigo header, fix colors and hovers
Summary: This adds Phacility "Indigo" as well as uses rgba for colors and hovers improving icon colors.
Test Plan:
Tested each color and hover states. Set test instance to scootaloo.
{F310660}
Reviewers: btrahan, epriestley
Reviewed By: epriestley
Subscribers: Korvin, epriestley
Differential Revision: https://secure.phabricator.com/D11836