Helm chart lack of support for 'labels:' field in values

I have noticed that the current Helm charts do not support the 'labels:' field in the values.yaml file. Also, there's no reference to this field in any of the templates files.

This can lead to considerable limitations when trying to further customize our deployments or service setups. Being able to specify additional labels in the 'values.yaml' file would be an important and useful feature.
