As an admin, I need to be able to add custom NB images to the cluster, so users can select them for their projects.

We are planning to support custom NB images via UI feature as part of a separate epic. This story is to document the current process enabled for early customers, so it's a supported feature. This is an interim solution that shouldn't require any development work. This will need to be tested and documented.

Notes from the Release Planning meeting on 2/3/22 : 

• The scope of test is limited to see if the procedure documented on how to add the custom image is tested.
• Validating that the custom image itself will work is out of scope of test, since the custom image will not be supported officially.