gerrit: use pcloud oauth provider instead of auth-proxy

Change-Id: I555a05ca00c90e84d3c82f31ccd53a220feff344
diff --git a/charts/gerrit/templates/gerrit.configmap.yaml b/charts/gerrit/templates/gerrit.configmap.yaml
index 83c188c..cd1a6a9 100644
--- a/charts/gerrit/templates/gerrit.configmap.yaml
+++ b/charts/gerrit/templates/gerrit.configmap.yaml
@@ -1,5 +1,6 @@
 {{- $root := . -}}
 
+{{- if not .Values.gerrit.etc.existingConfigMapName }}
 apiVersion: v1
 kind: ConfigMap
 metadata:
@@ -28,6 +29,7 @@
       enabled = false
   {{- end }}
 ---
+{{- end }}
 apiVersion: v1
 kind: ConfigMap
 metadata:
diff --git a/charts/gerrit/templates/gerrit.stateful-set.yaml b/charts/gerrit/templates/gerrit.stateful-set.yaml
index 2669325..2fc33c9 100644
--- a/charts/gerrit/templates/gerrit.stateful-set.yaml
+++ b/charts/gerrit/templates/gerrit.stateful-set.yaml
@@ -257,7 +257,7 @@
       {{- end }}
       - name: gerrit-config
         configMap:
-          name: {{ .Release.Name }}-gerrit-configmap
+          name: {{ if .Values.gerrit.etc.existingConfigMapName }}{{ .Values.gerrit.etc.existingConfigMapName }}{{ else }} {{ .Release.Name }}-gerrit-configmap{{ end }}
       - name: gerrit-secure-config
         secret:
           secretName: {{ .Release.Name }}-gerrit-secure-config
diff --git a/charts/gerrit/values.yaml b/charts/gerrit/values.yaml
index ef27520..c23f55c 100644
--- a/charts/gerrit/values.yaml
+++ b/charts/gerrit/values.yaml
@@ -256,6 +256,8 @@
   priorityClassName:
 
   etc:
+    # If provided config section below will be ignored.
+    existingConfigMapName: ""
     # Some values are expected to have a specific value for the deployment installed
     # by this chart to work. These are marked with `# FIXED`.
     # Do not change them!