Support prometheus proxy export

[hopugop]

TF provider should allow users to enable "export metrics" when creating a cluster.

[rjeczalik]

What should be the desired user interface, can you provide more details?

I think just mimicking the "Export metrics" checkbox from the UI is not enough, because an automation would want also to configure the scrapping from our proxy.

This needs more details.

[hopugop]

Mimicking the "Export metrics" checkbox from the UI is enough for this issue.

[rjeczalik]

Mimicking the "Export metrics" checkbox from the UI is enough for this issue.

It is not enough for the issue, in Terraform Provider support for a feature needs to be complete.

If we allow to enable certain functionality through the resource attributes, we need to provide a way to consume them.

The list of features for the cluster resource will be ever-growing - we should discuss sooner than later how to find a better way of introducing them, rather than just keep adding new attributes. New attributes requires handling of old state files. Maybe it would be better to create another add-on resource, like scylladbcloud_cluster_metrics? I would prefer this way, as it does not touch the cluster, extending it with more responsibilities.

Regardless whatever the final design, before we can implement this, there should be a formal proposal what and how to implement.