observability plugin - URLs and passwords

While trying out the observability plugin in 2023.2/edge a few thoughts came to mind.

Its really easy to enable and to retrieve the dashboard-url however I think that users need a bit more information than this to get started with this feature.

Really we should direct them to the catalogue landing page which then has links to grafana, prometheus and alertmanager - users will also need credentials to access some of these services (grafana only right now).

My proposal would be that the dashboard-url plugin command would point users to the catalogue landing page and provide them with any required credentials for access.

Note that this only applies for embedded COS only - remote COS (not yet implemented) would not need to have these features.