Add service//channel name outputs

Author: Steven Nemetz

modules/pagerduty/outputs.tf

@@ -0,0 +1,4 @@
+output "datadog_service_name" {
+  description = "Datadog service name for Pagerduty service"
+  value       = "${var.service_name}"
+}

modules/slack/outputs.tf

@@ -0,0 +1,4 @@
+output "datadog_service_name" {
+  description = "Datadog service name for Slack channel"
+  value       = "${var.channel_name}"
+}