Add ability to configure whether to deploy kpi-exporter

Also, add release name as a prefix to kpi-exporter resource names to
in line with other resources created by nem-monitoring.

Change-Id: I2b15f97128795e19d56a1be2a9290e8775f389e2
diff --git a/nem-monitoring/templates/exporter-configmap.yaml b/nem-monitoring/templates/exporter-configmap.yaml
index 69d2ae3..6107f7e 100644
--- a/nem-monitoring/templates/exporter-configmap.yaml
+++ b/nem-monitoring/templates/exporter-configmap.yaml
@@ -1,7 +1,9 @@
+{{- if .Values.kpi_exporter.enabled }}
 apiVersion: v1
 kind: ConfigMap
 metadata:
-  name: exporter-configmap
+  name: {{ template "kpi-exporter.fullname" . }}
 data:
   conf.yaml: |
 {{ include "exporter.config" . | indent 4 }}
+{{- end }}