ClusterSpec.SidecarImage does not endup anywhere

[dkropachev]

Describe the bug
Deploy cluster with SidecarImage defined or without it does not make any difference

To Reproduce
Steps to reproduce the behavior:

1. Create Operator ...
2. Deploy scylla cluster with SidecarImage defined:

spec:
  version: 4.2.0
  agentVersion: 2.2.0
  developerMode: true
  sidecarImage: 
    version: 1.32.0
    repository: busybox

3. Run "kubectl get pods -n scylla -o yaml | grep busybox" and you see nothing

Expected behavior
To see that sidecar image actually endup in the pod