[Reseller] Demo GitLab functionality

Problem

With Allow customers that purchased via Reseller to ... (&8941 - closed) hitting a milestone where we have Reseller accounts in production we should communicate to our stakeholders and team members what the feature is and what the value is

Proposal

Demo the feature - Could be a video, a gif, a bunch of screenshots, documentation.

Things that should be covered:

• alert on GitLab
• hidden buttons on /billing page
• Any other functionality introduced in [Reseller] Add message letting user know that t... (&10513 - closed)

Result

Changes to the reseller subscriptions on GitLab.com

Case	Video
Changes to the Usage quotas page on Seats, Pipelines and Storage tabs. When user intends to buy additional seats, minutes or storage - show a modal window
Changes to the Billing page. 1. Don't show Add seats button. 2. Don't show Renew button, even when the subscription is up for renew.