vdk-jupyter: impelement manual oauth2 login workflow

[antoniivanov]

When jupyter notebook is deployed in a Multi-Notebook server instance (like jupyterhub) each user instance has a distinct URL. This means we don’t have a stable redirect URL to register with your OAuth2 provider.

User Scenario

1. Every time a user starts a new notebook server, it gets a unique URL to their notebook
2. OAuth2 Challenge: Since the redirect URL is dynamic based on the instance, we can’t pre-register a fixed callback URL with the OAuth provider.

Given this setup there are a couple of solution
A) The authorization provider could allow dynamic URLs (not very likely as it's not very secure)

B) The Notebook parent server could provide stable proxy to the underlyng notebook (so we can use http://jupyterhub/notebook?user=xxx and parent server would proxy this call to the user's notebook server). This way only the query paramter is dynamic which is often ok with authorization providers. The registered notebook url woudl be http://jupyterhub/notebook

C) If none of the above works , this solution is proposed where we can use Manual Login where user would need to copy one URL into the application.

Here is a short gif showing the process:

[antoniivanov]

Note : this is a stacked PR (https://benjamincongdon.me/blog/2022/07/17/In-Praise-of-Stacked-PRs/) . So will be merged after PR #2590 is merged

[duyguHsnHsn]

The design seems a little bit off to me. Maybe changing the style of the listed items would make it look better and maybe the first button should be blue as the other "Ok" and "Continue" buttons from the Jupyter UI.