feat(DesignTokens): add text design tokens

mentioned in commit 4256fdae

mentioned in merge request status-page!901 (merged)

mentioned in merge request gitlab-org/frontend/playground/accessibility-scanner!26 (closed)

mentioned in merge request gitlab-org/frontend/pajamas-adoption-scanner!300 (merged)

mentioned in merge request status-page!903

mentioned in merge request gitlab-org/gitlab-services/design.gitlab.com!3763 (merged)

mentioned in merge request gitlab-org/gitlab-services/design.gitlab.com!3764 (merged)