Projected volumes for /srv/cfg

[nvanlaerebeke]

I needed support for adding the conf.php as a secret due to it containing the database password.

Previously it was possible to configure it in the values file in configs: {} but that means putting everything in the values file.
Another possibility was to use extraVolumes and extraVolumeMounts, but the config file needs to be put in /srv/cfg and will conflict with the other volume mounts already in the chart.

A solution to combine everything is to use a projected volume.
This allows the following configuration where a list of secrets and config maps can be given:

configsAsProjected: true
configsProjected:
  defaultMode: 420
  secrets:
    - privatebin-secret
  configMaps:
    - privatebin-extraconfig

Example secret:

apiVersion: v1
kind: Secret
metadata:
  name: privatebin-secret
  namespace: default
data:
  conf.php: >-
    ...
type: Opaque