fix(helm/templates) documentation and helm chart

[brodul]

The kubectl apply described in documentation does not work. The ClusterRoleBinding references a Service Account in kube-system. If you don't add the namespace parameter the objects will be created in the default namespace. Therefore the role binding will not find the service account. If you create all of the objects in the kube-system the apply will work.

In helm templates the deploy is missing the serviceAccountName therefore the default ServiceAccount will be used that does not have the permissions for the metrics server.

This fixes #33 . I can fix the namespace referencing in a more Helm way (see https://helm.sh/docs/chart_template_guide/builtin_objects/ Release.Namespace ), if you want to except the PR. You will have to install the chart with the -n parameter. The current approach could have issues with Helm3 (helm3 relies on namespace namespacing)

[phspagiari]

Thanks @brodul! 🚀 I'm just changing the title to match with our commit style guideline (since we use squash as default).