feat: add namespace overrides (#10539)

* feat: add namespace overrides

* add value in readme

* fix: readme description

* fix: description in value

* fix: set max length and trim last "-"

charts/ingress-nginx/templates/default-backend-rolebinding.yaml

@@ -9,7 +9,7 @@ metadata:
     {{- toYaml . | nindent 4 }}
     {{- end }}
   name: {{ include "ingress-nginx.fullname" . }}-backend
-  namespace: {{ .Release.Namespace }}
+  namespace: {{ include "ingress-nginx.namespace" . }}
 roleRef:
   apiGroup: rbac.authorization.k8s.io
   kind: Role
@@ -17,5 +17,5 @@ roleRef:
 subjects:
   - kind: ServiceAccount
     name: {{ template "ingress-nginx.defaultBackend.serviceAccountName" . }}
-    namespace: {{ .Release.Namespace | quote }}
+    namespace: {{ (include "ingress-nginx.namespace" .) | quote }}
 {{- end }}