[Feature Request] Allow to override Kubernetes cluster name from cluster.local to a custom domain

[kadishmal]

As already reported in the sibling repo rustfs/rustfs#3857, it is very important to allow to override clusterDomain via Helm values. At the moment RUSTFS_VOLUMES always uses the hardcoded .cluster.local as the root cluster domain. However, in our production environment we use a custom cluster domain which causes the operator to fail to create a tenant.

At the moment due to hardcoded cluster.local domain the following error occurs when deploying a tenant with TLS enabled:

Last Error Message:   TLS certificate in Secret 'prod-rustfs-private-certificate-secret' key 'tls.crt' 
does not cover required DNS names: prod-rustfs-mse-nvme-500-0.prod-rustfs-hl.mse.svc.cluster.local, 
prod-rustfs-mse-nvme-500-1.prod-rustfs-hl.mse.svc.cluster.local, 
prod-rustfs-mse-nvme-500-2.prod-rustfs-hl.mse.svc.cluster.local, 
prod-rustfs-hl.mse.svc, prod-rustfs-hl.mse.svc.cluster.local, prod-rustfs-io.mse.svc, 
prod-rustfs-io.mse.svc.cluster.local

The following DNS names are covered in the private certificate issued by CertManager:

dnsNames:
  - prod-rustfs-hl.mse.svc.k8s.mse.cloud
  - '*.prod-rustfs-hl.mse.svc.k8s.mse.cloud'