Configure RabbitMQ to use my own PVC

### Is your feature request related to a problem? Please describe. Seems that RabbitMQCluster Operator simply ignores any existing PVC and tries to create its own. I have attempted several variations of the yaml file to get this working ``` apiVersion: rabbitmq.com/v1beta1 kind: RabbitmqCluster metadata: labels: app: rabbitmq name: rabbitm namespace: mynamepsace spec: replicas: 1 image: rabbitmq:latest service: type: ClusterIP persistence: existingClaim: pvclaim-winrabbitmq resources: requests: cpu: 256m memory: 1Gi limits: cpu: 256m memory: 1Gi rabbitmq: additionalPlugins: - rabbitmq_management - rabbitmq_peer_discovery_k8s additionalConfig: | default_user = admin default_pass = adminpassword advancedConfig: "" ``` This is default persistence bit. ``` persistence: storageClassName: "" storage: 10Gi ``` I have tried other things like ``` persistence: existingClaim: ClameName: pvclaim-winrabbitmq ``` I also tried adding in the volume ``` volumes: - name: pvc-mount persistentVolumeClaim: claimName: pvclaim-winrabbitmq ``` There doesn't appear to be any configurable option here for an existing PVC that we have setup using NFS or CSi to ensure the PVC is persistent between pod restarts. ### Describe the solution you'd like I want to take my persistent volume (PV) and claim (PVC) created before hand I already have the PV example PVC: ``` apiVersion: v1 kind: PersistentVolumeClaim metadata: name: pvclaim-winrabbitmq spec: storageClassName: "" accessModes: - ReadWriteMany resources: requests: storage: 10Gi volumeName: pv-winrabbitmq ``` and tell RabbitMQCluster Operator to stop creating the the one called "persistence-rabbitmq-server-0" which fails because I need persistence not local storage class ### Describe alternatives you've considered I was using bitnami charts previously but now they are giving us imagepullback errors. Arrow does not respond in anyway or form to the access requests on the website, and if I phone them they seem unable to help, no one there has ever heard of bitnami or rabbitmq, so therefore they are seemingly unable to assist I have also tried adding the legacy repo and that also doesn't work and imagepullback errors is all you get. Seems there is no paid or free way to make this work properly. This was the best solution and it doesn't work anymore... Our Helm deployment looked like this: ``` helm install rabbitmq-alpha bitnami/rabbitmq --namespace ourapp-alpha \ --set replicaCount=1 \ --set volumePermissions.enabled=true \ --set clustering.forceBoot=true \ --set podManagementPolicy=Parallel \ --set auth.username=admin,auth.password=adminpassword \ --set namespaceOverride=ourapp-alpha \ --set readinessProbe.enabled=false \ --set service.type=LoadBalancer \ --set persistence.existingClaim=pvclaim-winrabbitmq-alpha ``` Maybe some better documentation for NON developers (IT Admins) to be able to setup and manage RabbitMQ? ### Additional context https://www.rabbitmq.com/blog/2020/08/10/deploying-rabbitmq-to-kubernetes-whats-involved#use-a-persistent-volume-for-node-data we do not want to use this for persistence either. Quite simply it doesn't fit the environment.