Change favicon color according to build status

It would be awesome if GitLab CI would change the favicon color according to the build status of the current page. Travis CI for example does that too and it makes it quite easy to spot the failing build if you have multiple tabs open.

Good idea

/cc @dzaporozhets

Moved from gitlab-org/gitlab-ci#329

Added 19173 gitlab-foss14213 labels

moved from gitlab-foss#23402 (moved)