feat(config): support setting the cluster domain

!7 #12

templates/k3s-config.yaml.j2

@@ -6,7 +6,16 @@
 # Dont edit this file directly as it will be overwritten.
 #
 
-{% if Kubernetes_Prime | default(false) | bool -%}cluster-cidr: "{{ KubernetesPodSubnet }}"{% endif %}
+{% if Kubernetes_Prime | default(false) | bool -%}
+cluster-cidr: "{{ KubernetesPodSubnet }}"
+cluster-domain: {% if 
+                      kubernetes_config.cluster.domain_name is defined
+                        and
+                      kubernetes_config.cluster.domain_name | default('') != ''
+                -%}
+                    {{ kubernetes_config.cluster.domain_name }}
+                {%- endif %}
+{%- endif %}
 
 {% if Kubernetes_Master | default(false) -%}cluster-init: true
 disable-network-policy: true