fix(deploy): use Recreate strategy to fit tenant CPU quota

Single-replica deployment with tight CPU quota (1 core) cannot run two
pods simultaneously during a rolling update. Recreate kills the old pod
before starting the new one.

backend/deploy/helm/templates/deployment.yaml

@@ -9,6 +9,8 @@ spec:
   {{- if not .Values.autoscaling.enabled }}
   replicas: {{ .Values.replicaCount }}
   {{- end }}
+  strategy:
+    type: Recreate
   selector:
     matchLabels:
       {{- include "marktvogt-backend.selectorLabels" . | nindent 6 }}