Ensure /etc/resolv.conf content for CoreOS

Use cloud-init config to replace /etc/resolv.conf with the
content for kubelet to properly configure hostnet pods.

Do not use systemd-resolved yet, see
https://coreos.com/os/docs/latest/configuring-dns.html
"Only nss-aware applications can take advantage of the
systemd-resolved cache. Notably, this means that statically
linked Go programs and programs running within Docker/rkt
will use /etc/resolv.conf only, and will not use the
systemd-resolve cache."

Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>

roles/dnsmasq/templates/resolvconf.j2

@@ -0,0 +1,10 @@
+#cloud-config
+write_files:
+  - path: "/etc/resolv.conf"
+    permissions: "0644"
+    owner: "root"
+    content: |
+    {% for l in cloud_config.stdout_lines %}
+      {{ l }}
+    {% endfor %}
+    #