Remove unofficial bare-metal *_networkds variables

* Remove controller_networkds and worker_networkds variables. These
variables were always listed as experimental, unsupported, and excluded
from documentation in anticipation of Container Linux Config snippets
* Use Container Linux Config snippets on bare-metal instead. They
provide safer, more powerful, and more elegant host customization

bare-metal/container-linux/kubernetes/cl/controller.yaml.tmpl

@@ -163,8 +163,6 @@ storage:
             --net=host \
             --dns=host \
             --exec=/bootkube -- start --asset-dir=/assets "$@"
-networkd:
-  ${networkd_content}
 passwd:
   users:
     - name: core

bare-metal/container-linux/kubernetes/cl/worker.yaml.tmpl

@@ -96,8 +96,6 @@ storage:
       contents:
         inline: |
           fs.inotify.max_user_watches=16184
-networkd:
-  ${networkd_content}
 passwd:
   users:
     - name: core

bare-metal/container-linux/kubernetes/profiles.tf

@@ -142,9 +142,6 @@ data "template_file" "controller-configs" {
     k8s_dns_service_ip    = "${module.bootkube.kube_dns_service_ip}"
     cluster_domain_suffix = "${var.cluster_domain_suffix}"
     ssh_authorized_key    = "${var.ssh_authorized_key}"
-
-    # Terraform evaluates both sides regardless and element cannot be used on 0 length lists
-    networkd_content = "${length(var.controller_networkds) == 0 ? "" : element(concat(var.controller_networkds, list("")), count.index)}"
   }
 }
 
@@ -174,9 +171,6 @@ data "template_file" "worker-configs" {
     k8s_dns_service_ip    = "${module.bootkube.kube_dns_service_ip}"
     cluster_domain_suffix = "${var.cluster_domain_suffix}"
     ssh_authorized_key    = "${var.ssh_authorized_key}"
-
-    # Terraform evaluates both sides regardless and element cannot be used on 0 length lists
-    networkd_content = "${length(var.worker_networkds) == 0 ? "" : element(concat(var.worker_networkds, list("")), count.index)}"
   }
 }
 

bare-metal/container-linux/kubernetes/variables.tf

@@ -141,17 +141,3 @@ variable "kernel_args" {
   type        = "list"
   default     = []
 }
-
-# unofficial, undocumented, unsupported, temporary
-
-variable "controller_networkds" {
-  type        = "list"
-  description = "Controller Container Linux config networkd section"
-  default     = []
-}
-
-variable "worker_networkds" {
-  type        = "list"
-  description = "Worker Container Linux config networkd section"
-  default     = []
-}