Move kube_feature_gates to kubelet config (#8048)

to remove deprecation warning:

> Flag --feature-gates has been deprecated, This parameter should be set via the config file specified by the Kubelet's --config flag.

roles/kubernetes/node/templates/kubelet-config.v1beta1.yaml.j2

@@ -84,6 +84,12 @@ resolvConf: "{{ kube_resolv_conf }}"
 {% if inventory_hostname in groups['kube_node'] and kubelet_node_config_extra_args %}
 {{ kubelet_node_config_extra_args | to_nice_yaml(indent=2) }}
 {% endif %}
+{% if kube_feature_gates %}
+featureGates:
+{% for feature in kube_feature_gates %}
+  {{ feature|replace("=", ": ") }}
+{% endfor %}
+{% endif %}
 {% if tls_min_version is defined %}
 tlsMinVersion: {{ tls_min_version }}
 {% endif %}

roles/kubernetes/node/templates/kubelet.env.v1beta1.j2

@@ -34,7 +34,7 @@ KUBELET_HOSTNAME="--hostname-override={{ kube_override_hostname }}"
 {%   endif %}
 {% endif %}
 
-KUBELET_ARGS="{{ kubelet_args_base }} {% if node_taints|default([]) %}--register-with-taints={{ node_taints | join(',') }} {% endif %} {% if kube_feature_gates %} --feature-gates={{ kube_feature_gates|join(',') }} {% endif %} {% if kubelet_custom_flags is string %} {{kubelet_custom_flags}} {% else %}{% for flag in kubelet_custom_flags %} {{flag}} {% endfor %}{% endif %}{% if inventory_hostname in groups['kube_node'] %}{% if kubelet_node_custom_flags is string %} {{kubelet_node_custom_flags}} {% else %}{% for flag in kubelet_node_custom_flags %} {{flag}} {% endfor %}{% endif %}{% endif %}"
+KUBELET_ARGS="{{ kubelet_args_base }} {% if node_taints|default([]) %}--register-with-taints={{ node_taints | join(',') }} {% endif %} {% if kubelet_custom_flags is string %} {{kubelet_custom_flags}} {% else %}{% for flag in kubelet_custom_flags %} {{flag}} {% endfor %}{% endif %}{% if inventory_hostname in groups['kube_node'] %}{% if kubelet_node_custom_flags is string %} {{kubelet_node_custom_flags}} {% else %}{% for flag in kubelet_node_custom_flags %} {{flag}} {% endfor %}{% endif %}{% endif %}"
 {% if kubelet_flexvolumes_plugins_dir is defined %}
 KUBELET_VOLUME_PLUGIN="--volume-plugin-dir={{ kubelet_flexvolumes_plugins_dir }}"
 {% endif %}