use nginx proxy on non-master nodes to proxy apiserver traffic

Also adds all masters by hostname and localhost/127.0.0.1 to
apiserver SSL certificate.

Includes documentation update on how localhost loadbalancer works.

roles/kubernetes/node/tasks/nginx-proxy.yml

@@ -0,0 +1,9 @@
+---
+- name: nginx-proxy | Write static pod
+  template: src=manifests/nginx-proxy.manifest.j2 dest=/etc/kubernetes/manifests/nginx-proxy.yml
+
+- name: nginx-proxy | Make nginx directory
+  file: path=/etc/nginx state=directory mode=0700 owner=root
+
+- name: nginx-proxy | Write nginx-proxy configuration
+  template: src=nginx.conf.j2 dest="/etc/nginx/nginx.conf" owner=root mode=0755 backup=yes