Respect http_proxy settings in helm wrapper

roles/kubernetes-apps/helm/templates/helm-container.j2

@@ -2,6 +2,9 @@
 {{ docker_bin_dir }}/docker run --rm \
   --net=host \
   --name=helm \
+  {% if http_proxy %}-e HTTP_PROXY={{ http_proxy }} \{% endif %}
+  {% if https_proxy %}-e HTTPS_PROXY={{ https_proxy }} \{% endif %}
+  {% if no_proxy %}-e NO_PROXY={{ no_proxy }} \{% endif %}
   -v /etc/ssl:/etc/ssl:ro \
   -v {{ helm_home_dir }}:{{ helm_home_dir }}:rw \
   {% for dir in ssl_ca_dirs -%}