Kubespray NVIDIA GPU support

kubespray-vars.yml

## Override Docker install vars to install version compatible with nvidia-docker2
docker_version: '17.03.2'

docker_versioned_pkg:
  '17.03.2': docker-ce=17.03.2~ce-0~ubuntu-xenial

docker_package_info:
  pkg_mgr: apt
  pkgs:
    - name: "{{ docker_versioned_pkg[docker_version | string] }}"
      force: yes

docker_apt_repo_gpgkey: 'https://download.docker.com/linux/ubuntu/gpg'
docker_apt_repo_base_url: 'https://download.docker.com/linux'
docker_repo_key_info:
  pkg_key: apt_key
  url: '{{ docker_apt_repo_gpgkey }}'
  repo_keys:
    - 9DC858229FC7DD38854AE2D88D81803C0EBFCD88

docker_repo_info:
  pkg_repo: apt_repository
  repos:
    - deb [arch=amd64] {{ docker_apt_repo_base_url }}/{{ ansible_distribution|lower }} {{ ansible_distribution_release|lower }} stable