Add configmap for xds (#18264)

Signed-off-by: Shunki Fujiwara <shunki-fujiwara@freee.co.jp>

stable/envoy/Chart.yaml

@@ -1,7 +1,7 @@
 apiVersion: v1
 description: Envoy is an open source edge and service proxy, designed for cloud-native applications.
 name: envoy
-version: 1.8.0
+version: 1.8.1
 appVersion: 1.11.2
 keywords:
 - envoy

stable/envoy/templates/xds.configmap.yaml

@@ -0,0 +1,15 @@
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: {{ template "envoy.fullname" . }}-xds
+  labels:
+    app: {{ template "envoy.name" . }}
+    chart: {{ template "envoy.chart" . }}
+    release: {{ .Release.Name }}
+    heritage: {{ .Release.Service }}
+data:
+{{- range $filename, $content := .Values.xds }}
+  {{ tpl $filename $ }}: |-
+{{ $valueWithDefault := default "" $content -}}
+{{ tpl $valueWithDefault $ | indent 4 }}
+{{- end -}}