* Add test template example for helm create

As helm create ganerates an nginx chart, the example is based on
https://github.com/helm/helm/blob/master/docs/examples/nginx/templates/
service-test.yaml
Signed-off-by: Martin Hickey <martin.hickey@ie.ibm.com>

* Update after review

- https://github.com/helm/helm/pull/4524#pullrequestreview-155183390
- https://github.com/helm/helm/pull/4524#pullrequestreview-155379922
- Fix where app.kubernetes.io/instance was incorrect in service selector
Signed-off-by: Martin Hickey <martin.hickey@ie.ibm.com>

* Add doc update
Signed-off-by: Martin Hickey <martin.hickey@ie.ibm.com>

* Update GO formatting
Signed-off-by: Martin Hickey <martin.hickey@ie.ibm.com>