[watsonx-self-managed-ocp] Add a terraform output for the dashboard url

Add a terraform output for the dashboard url. Pod logs show this:

```
--- Cloud Pak for Data project cpd ---
CP4D URL: https://cpd-cpd.con-cluster-065597c376bf4b3ab6ffebaa0efea154-0000.us-south.containers.appdomain.cloud
```