Generate CI-related secrets instead of hard-coding them in the values

The auth chart is a purely CI-focussed chart used to set up secrets for the other charts to consume. At the moment, we hardcode the secrets to generate in the values file. This is not very flexible and despite it being ci-only it is best not to have hardcoded secrets in our codebase.

This can be replaced by a script to generate these items. This will involve talking to the Kubernetes API to generate secrets/configmaps from within a pod.