Improved OIDC redirect response

[MikeNeilson]

Currently the way the new AuthCode + PKCE works opens a browser but doesn't close it's tab and move back to the client.
The client can easily grab focus and move to top, and should. However, the redirect handler should provide a useful message to the user if it does not, or just doesn't work.

@krowvin made this for cwms-cli, once it opens the PR and the code is present. We should definitely copy it in and adjust links as appropriate.

[krowvin]

here is the file from the PR that renders that

https://github.com/HydrologicEngineeringCenter/cwms-cli/pull/155/changes#diff-cdd1af65b72fd3aa8efde29f0ea791f7de76b39c1cb0b69865289b80788e82ee