[Redesign] Add back limited header-color options
Summary: Ref T8099. Adds back basic header color options, which change the logo color instead. Also RAINBOW.
Test Plan:
tested each of the new colors.
Reviewers: btrahan, epriestley
Reviewed By: epriestley
Subscribers: Korvin, epriestley
Maniphest Tasks: T8099
Differential Revision: https://secure.phabricator.com/D13040