[Redesign] Blindigo logo
Summary: Ref T8099. Update logo and font to use Blindigo (tm) color system. Also tweak hover backgrounds a hair.
Test Plan: Photoshop.
Reviewers: btrahan, epriestley
Reviewed By: epriestley
Subscribers: Korvin, epriestley
Maniphest Tasks: T8099
Differential Revision: https://secure.phabricator.com/D12753