Add overage info card

What does this MR do and why?

The MR adds an overage info card, it's controlled by a backend variable (will be changed later on the backend).

The card shows overage terms related copy with a button linking to the CDot (link will be changed later on the backend).

References

gitlab-org/customers-gitlab-com#14084

Screenshots or screen recordings

Before	After

How to set up and validate locally

Using storybook:

• yarn storybook:start
• visit http://localhost:6006/?path=/docs/ee-usage-quotas-usage-billing-app--docs

Using gdk:

• Ensure you've a subscription added to your group
• Enable billing_usage_dev feature flag (e.g. http://gdk.test:3000/rails/features/usage_billing_dev)
• Navigate to the Admin area > GitLab Duo > Usage dashboard (e.g. http://gdk.test:3000/groups/gitlab-org/-/settings/gitlab_duo/usage)

MR acceptance checklist

Evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.