Prometheus Operator, server and metrics gathering overlay

[tomncooper]

We should add an overlay that includes the installation of the Prometheus Operator, server and the necessary configs for the various components to allow metrics scraping. The main aim is to make sure all the Console's various metrics charts are populated.

The current install deletes the Console's ServiceMonitor so we will need to reinstate that in this overlay.

[tomncooper]

Would we also want to include a graphana overlay using the example dashboards 🤔