Replace cronjobs.yml with Helm chart

[snpdev]

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

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 cronjobs OpenShift Template with a Helm chart.

# Generate cronjobs if service type defines them
  SERVICE_CRONJOB_FILE="/oc-build-deploy/openshift-templates/${SERVICE_TYPE}/cronjobs.yml"
  if [ -f $SERVICE_CRONJOB_FILE ]; then
    CRONJOB_COUNTER=0
    while [ -n "$(cat ${SERVICE_CRONJOB_FILE} | shyaml keys $CRONJOB_COUNTER 2> /dev/null)" ]
do
...
done
fi

https://github.com/amazeeio/lagoon/blob/master/images/oc-build-deploy-dind/build-deploy-docker-compose.sh#L558-L577

[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.