report status related the notebook server startup in Notebook resource

[christianvogt]

/kind feature

Why you need this feature:
[Is your feature request related to a problem? Please describe in details]
The ODH dashboard reports the progress of a notebook server startup to the user as well as reports any errors that occurred during this process. It does this today by identifying the pod related to the notebook and then inspecting the events of the pod (see here). This however is error prone and subject change.

If the pod never starts then the UI needs to start looking elsewhere to find the cause. For example if there is a LimitRange that prevents the StatefulSet from starting a pod, the StatefulSet events will report this error.

Furthermore if there was already a StatefulSet that existed in the namespace with the exact same name of a newly created Notebook, then the Notebook will never start and there's no where this error gets reported.

Describe the solution you'd like:
[A clear and concise description of what you want to happen.]

It would be best if the Notebook reported all relevant information in its status. Clients shouldn't have to know the implementation details and look for other related resources just to obtain the status of the Notebook.