Port "Simplify admin instance licenses page"

Ports CE changes to include a license app
scss variable and a jest import alias.

app/assets/stylesheets/framework/variables.scss

@@ -719,3 +719,8 @@ $compare-branches-sticky-header-height: 68px;
  - Issue: https://gitlab.com/gitlab-org/design.gitlab.com/issues/242
  */
 $enable-validation-icons: false;
+
+/*
+Licenses
+*/
+$license-header-cell-width: 150px;