chore: add polardbx addon file (#5622)

(cherry picked from commit a1a1885)

helm/templates/addons/polardbx-addon.yaml

@@ -0,0 +1,28 @@
+apiVersion: extensions.kubeblocks.io/v1alpha1
+kind: Addon
+metadata:
+  name: polardbx
+  labels:
+    {{- include "kubeblocks.labels" . | nindent 4 }}
+    "kubeblocks.io/provider": community
+  {{- if .Values.keepAddons }}
+  annotations:
+    helm.sh/resource-policy: keep
+  {{- end }}
+spec:
+  description: 'PolarDB-X is a cloud native distributed SQL Database designed for high concurrency, massive storage, complex querying scenarios.'
+  type: Helm
+  helm:
+    {{- include "kubeblocks.addonChartLocationURL" ( dict "name" "polardbx" "version" (default .Chart.Version .Values.versionOverride) "values" .Values) | indent 4 }}
+    {{- include "kubeblocks.addonChartsImage" . | indent 4 }}
+
+    installOptions:
+     {{- if hasPrefix "oci://" .Values.addonChartLocationBase }}
+      version: {{ default .Chart.Version .Values.versionOverride }}
+     {{- end }}
+
+  installable:
+    autoInstall: false
+
+  defaultInstallValues:
+    - enabled: true