LP#1960526: adjust link color on Angular and AngularJS staff interfaces

LP#1960526: adjust link color on Angular and AngularJS staff interfaces

Change the default link blue on the Angular and AngularJS interfaces
to #255a88. This achieves two things:

- Improves the color contrast on the AngularJS side against a white
  background from AA for normal text to AAA.
- Improves the Angular side so that it meets AAA color contrast for
  normal and large text, instead of meeting only AA for large text.

Signed-off-by: Galen Charlton <gmc@equinoxOLI.org>
Signed-off-by: Garry Collum <gcollum@gmail.com>