[v2] handling non existent service account

[nluaces]

Describe the bug If a site is created with a service account that does not exist, the replicaset fails to create a skupper-router pod, the site is showing active status.

How To Reproduce Steps to reproduce the behavior:

• create namespaces: skupper and north
• apply CRDs and deploy skupper cluster-scoped controller in the skupper namespace.
• create a site in the north namespace using the CLI
• check that there are no router pods in the north namespace

Expected behavior

• this error is reported in the site status

Additional context

kubectl describe replicaset skupper-router-7dc8c5fbf9 -n north       
Name:           skupper-router-7dc8c5fbf9
Namespace:      north
Selector:       pod-template-hash=7dc8c5fbf9,skupper.io/component=router
Labels:         app.kubernetes.io/name=skupper-router
                app.kubernetes.io/part-of=skupper
                application=skupper-router
                pod-template-hash=7dc8c5fbf9
                skupper.io/component=router
                skupper.io/group=skupper-router
                skupper.io/type=site
Annotations:    deployment.kubernetes.io/desired-replicas: 1
                deployment.kubernetes.io/max-replicas: 2
                deployment.kubernetes.io/revision: 1
Controlled By:  Deployment/skupper-router
Replicas:       0 current / 1 desired
Pods Status:    0 Running / 0 Waiting / 0 Succeeded / 0 Failed
Pod Template:
  Labels:           app.kubernetes.io/name=skupper-router
                    app.kubernetes.io/part-of=skupper
                    application=skupper-router
                    pod-template-hash=7dc8c5fbf9
                    skupper.io/component=router
                    skupper.io/group=skupper-router
                    skupper.io/type=site
  Annotations:      prometheus.io/port: 9090
                    prometheus.io/scrape: true
                    skupper.io/config-digest: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
  Service Account:  skupper-controller
  Containers:
   router:
    Image:       quay.io/skupper/skupper-router:main
    Ports:       5671/TCP, 9090/TCP, 55671/TCP, 45671/TCP
    Host Ports:  0/TCP, 0/TCP, 0/TCP, 0/TCP
    Liveness:    http-get http://:9090/healthz delay=60s timeout=1s period=10s #success=1 #failure=3
    Readiness:   http-get http://:9090/healthz delay=1s timeout=1s period=10s #success=1 #failure=3
    Environment:
      APPLICATION_NAME:               skupper-router
      POD_NAMESPACE:                   (v1:metadata.namespace)
      POD_IP:                          (v1:status.podIP)
      QDROUTERD_AUTO_MESH_DISCOVERY:  QUERY
      QDROUTERD_CONF:                 /etc/skupper-router/config/skrouterd.json
      QDROUTERD_CONF_TYPE:            json
      SKUPPER_SITE_ID:                30e38069-2a00-4c1c-abde-4237a118018e
    Mounts:
      /etc/skupper-router-certs from skupper-router-certs (rw)
      /etc/skupper-router-certs/skupper-amqps/ from skupper-local-server (rw)
      /etc/skupper-router/config/ from router-config (rw)
   config-sync:
    Image:      quay.io/gordons/config-sync:v2-milestone1
    Port:       <none>
    Host Port:  <none>
    Readiness:  http-get http://:9191/healthz delay=1s timeout=1s period=10s #success=1 #failure=3
    Environment:
      SKUPPER_NAMESPACE:           (v1:metadata.namespace)
      SKUPPER_SITE_ID:            30e38069-2a00-4c1c-abde-4237a118018e
      SKUPPER_SITE_NAME:          north
      SKUPPER_CONFIG:             skupper-router
      SKUPPER_ROUTER_DEPLOYMENT:  skupper-router
    Mounts:
      /etc/skupper-router-certs from skupper-router-certs (rw)
  Volumes:
   skupper-local-server:
    Type:        Secret (a volume populated by a Secret)
    SecretName:  skupper-local-server
    Optional:    false
   router-config:
    Type:      ConfigMap (a volume populated by a ConfigMap)
    Name:      skupper-router
    Optional:  false
   skupper-router-certs:
    Type:       EmptyDir (a temporary directory that shares a pod's lifetime)
    Medium:     
    SizeLimit:  <unset>
Conditions:
  Type             Status  Reason
  ----             ------  ------
  ReplicaFailure   True    FailedCreate
Events:
  Type     Reason        Age                   From                   Message
  ----     ------        ----                  ----                   -------
  Warning  FailedCreate  4m35s (x17 over 10m)  replicaset-controller  Error creating: pods "skupper-router-7dc8c5fbf9-" is forbidden: error looking up service account north/skupper-controller: serviceaccount "skupper-controller" not found