feat: added extraVolumes and extraVolumeMounts to owncloud deployment

[astromechza]

This PR helps to address #66 by adding support for extra volume mounts. This allows additional config maps or volumes to be mounted in order to add or extend behavior. In the case of #66, this can be used to mount in a config map for use with OWNCLOUD_PRE_CRONJOB_PATH to run additional background behavior.

Tests?

Manually tested by modifying the default values.yaml and rendering locally and inspecting both deployment and cronjob.

$ helm template example ./charts/owncloud -f charts/owncloud/values.yaml
...
          volumeMounts:
            - name: owncloud-data
              mountPath: /mnt/data
            - name: config-volume
              mountPath: /mnt/data/config/configmap.config.php
              subPath: configmap.config.php
            - mountPath: /super-secret
              name: extra-volume
      volumes:
        - name: owncloud-data
          persistentVolumeClaim:
            claimName: example-owncloud
        - name: config-volume
          secret:
            secretName: owncloud-config
        - name: extra-volume
          secret:
            secretName: super-secret-volume
...

[xoxys]

Thanks! To fix the docs issue, you can run make docs and commit the changes.

[xoxys]

Needs to be added to the cronjob as well https://github.com/owncloud-docker/helm-charts/blob/main/charts/owncloud/templates/cronjob.yaml#L41

[astromechza]

Done and done 👍