Added example environment

 export CUSTOM_KUBECONFIG="cluster-example.kubeconfig"

 export VAULT_HOSTNAME=vault.example.org

 export DOMAIN1=*.example.production

 export DOMAIN2=*.example.staging

 export DOMAIN3=*.example.dev

 export PROMETHEUS_HOSTNAME=prometheus.example.production

 export CAPIF_HOSTNAME="capif.example.staging"

 export REGISTER_HOSTNAME="register.example.staging"

 export CAPIF_NAMESPACE=ocf-capif

 export CAPIF_CI_ENV_ENDPOINT=staging

 export CAPIF_DOMAIN=example.staging

 export CAPIF_IMAGE_TAG="v3.0.0-release"