Add Databricks Overwatch for Observability

[rportilla-databricks]

We should consider adding overwatch as part of the setup with a default of 'off'. The final decision on whether to add this needs to consider the setup cost and whether this is fully automatic with terraform. Project documentation here - https://databrickslabs.github.io/overwatch/

[alexott]

It's not relevant anymore as we have system tables now.