v2 -- Please add a coredns cluster metrics feature to satisfy the needs of the CoreDNS integration

[ceastman-r7]

The connection CoreDNS integration is looking for metrics coming from the job_name = "integrations/coredns"

Snippet of config from the integration page:

discovery.relabel "metrics_integrations_integrations_coredns" {
	targets = [{
		__address__ = "localhost:9153",
		cluster     = "cloud",
	}]

	rule {
		target_label = "instance"
		replacement  = constants.hostname
	}
}

prometheus.scrape "metrics_integrations_integrations_coredns" {
	targets    = discovery.relabel.metrics_integrations_integrations_coredns.output
	forward_to = [prometheus.relabel.metrics_integrations_integrations_coredns.receiver]
	job_name   = "integrations/coredns"
}

prometheus.relabel "metrics_integrations_integrations_coredns" {
	forward_to = [prometheus.remote_write.metrics_service.receiver]

	rule {
		source_labels = ["__name__"]
		regex         = "up|coredns_build_info|coredns_cache_entries|coredns_cache_hits_total|coredns_cache_misses_total|coredns_dns_request_duration_seconds_bucket|coredns_dns_request_size_bytes_bucket|coredns_dns_requests_total|coredns_dns_response_size_bytes_bucket|coredns_dns_responses_total|coredns_forward_healthcheck_broken_total|coredns_forward_healthcheck_failures_total|coredns_forward_request_duration_seconds_bucket|coredns_forward_requests_total|coredns_forward_responses_total|coredns_panics_total|coredns_plugin_enabled|go_goroutines|process_cpu_seconds_total|process_resident_memory_bytes"
		action        = "keep"
	}
}