feat(css): add 2 CSS utils
What does this MR do?
This adds 2 new CSS utils to be used in design.gitlab.com:
gl-gap-7
gl-grid-template-columns-4
We add those to replace some custom CSS utils that were added to design.gitlab.com
in gitlab-org/gitlab-services/design.gitlab.com!3113 (merged).
Edited by Paul Gascou-Vaillancourt