As a user, I want to be able to easily start using Anaconda after I subscribe to the service, so I can utilize the service in my Jupyter notebooks.

Anaconda will offer a specific NB image to service subscribers. We want to display the Anaconda image only to subscribers. Scope for this story:

• Provide method for users to validate Anaconda subscription in dashboard UI. 
• If successfully validated, we should show the Anaconda image as an option in the NB server spawner UI. We should also provide an option to have the Anaconda tile displayed under the 'Enabled' tab in the dashboard.