Use kube_config_dir for kubeconfig

The path of kubeconfig should be configurable, and its default value
is /etc/kubernetes/admin.conf. Most paths of the file are configurable
but some were not. This make those configurable.

roles/remove-node/pre-remove/tasks/main.yml

@@ -9,7 +9,7 @@
 
 - name: remove-node | Drain node except daemonsets resource  # noqa 301
   command: >-
-    {{ bin_dir }}/kubectl --kubeconfig /etc/kubernetes/admin.conf drain
+    {{ bin_dir }}/kubectl --kubeconfig {{ kube_config_dir }}/admin.conf drain
       --force
       --ignore-daemonsets
       --grace-period {{ drain_grace_period }}

roles/upgrade/post-upgrade/tasks/main.yml

@@ -1,6 +1,6 @@
 ---
 - name: Uncordon node
-  command: "{{ bin_dir }}/kubectl --kubeconfig /etc/kubernetes/admin.conf uncordon {{ kube_override_hostname|default(inventory_hostname) }}"
+  command: "{{ bin_dir }}/kubectl --kubeconfig {{ kube_config_dir }}/admin.conf uncordon {{ kube_override_hostname|default(inventory_hostname) }}"
   delegate_to: "{{ groups['kube_control_plane'][0] }}"
   when:
     - needs_cordoning|default(false)

roles/upgrade/pre-upgrade/tasks/main.yml

@@ -84,7 +84,7 @@
       delay: "{{ drain_retry_delay_seconds }}"
   rescue:
     - name: Set node back to schedulable
-      command: "{{ bin_dir }}/kubectl --kubeconfig /etc/kubernetes/admin.conf uncordon {{ inventory_hostname }}"
+      command: "{{ bin_dir }}/kubectl --kubeconfig {{ kube_config_dir }}/admin.conf uncordon {{ inventory_hostname }}"
       when: upgrade_node_uncordon_after_drain_failure
     - name: Fail after rescue
       fail: