data-plane-controller: escape hatch for broken nodes

[mdibaiee]

Sometimes we have nodes which are broken for infrastructure reasons (e.g. an etcd node that can no longer access internet) -- In these scenarios we need to manually nuke the instance, run a refresh and re-create it.

This is doable on normal data planes, but for BYOC we do not have access to nuke an instance ourselves.

This may be done using pulumi destroy --target "urn" --target-dependents

So an operator would do pulumi stack --show-urns and then ask data-plane-controller to destroy a specific resource.