[feature] Cluster link buttons

[ArcherSeven]

Problem Description

Currently, there is no simple method of navigating between Omni and our monitoring tools such as Grafana.

Solution

It would be nice if we could configure the cluster with an annotation for a link to a web page elsewhere: such as a Grafana dashboard associated with the cluster, or to the site configuration in our internal tools associated with the cluster.

Alternative Solutions

No response

Notes

Workload service proxy is awesome, and this is a similar kinda request but feels much much easier to implement.

Similar to https://argo-cd.readthedocs.io/en/stable/user-guide/external-url/

https://github.com/siderolabs/omni-feedback/issues/31