Update documentation to account for changes in RHODS-1585:

As a DS user, I want to be able to track the progress of starting the NB server, so I can take appropriate action if there are any issues.

Scope of story:

Design a solution to do the following, document the plan in this story:

1. Provide progress dialog per UX: https://marvelapp.com/prototype/28dc5af6/screen/78116144
2. Provide clear error messages in the case of any issues
3. Provide options to try again or cancel per UX

Spike Info: https://issues.redhat.com/browse/RHODS-601