Replace pvc.yml with Helm chart

[snpdev]

This is a sub-issue of https://github.com/amazeeio/lagoon/issues/564#issue-350184516, bullet 7:

Create more OpenShift Objects (Deployments, PVCs) based on the figured out services (happens in https://github.com/amazeeio/lagoon/blob/master/images/oc-build-deploy-dind/build-deploy-docker-compose.sh#L365-L495)

This issue specifically concerns the replacement of the PVC OpenShift Template with a Helm chart.

# Generate PVC if service type defines one
  OPENSHIFT_SERVICES_TEMPLATE="/oc-build-deploy/openshift-templates/${SERVICE_TYPE}/pvc.yml"
  if [ -f $OPENSHIFT_SERVICES_TEMPLATE ]; then
    OPENSHIFT_TEMPLATE=$OPENSHIFT_SERVICES_TEMPLATE
    .  /oc-build-deploy/scripts/exec-openshift-create-pvc.sh
fi

https://github.com/amazeeio/lagoon/blob/master/images/oc-build-deploy-dind/build-deploy-docker-compose.sh#L525-L530

[snpdev]

Closing. We are not creating a Helm chart for each K8s resource. Rather, we will have a Helm chart for each service, e.g. Varnish.