Telegraf-DS: support configuration of include/exclude labels

By default, the telegraf [kubernetes plugin](https://github.com/influxdata/telegraf/tree/master/plugins/inputs/kubernetes) excludes all pod labels. We use the "component" label to help us group metrics from a collection of identical pods whose names don't otherwise group them. Unfortunately, there is no way to add this to the include list in the telegraf-ds chart. Having that option would be useful.

Start with the telegraf-ds Helm chart and compare its current configuration with the linked Telegraf Kubernetes plugin documentation. Identify how chart values are rendered into the plugin configuration; done means users can configure included and excluded pod labels and the rendered chart preserves those settings.

Written by the indexing model from the issue text.