Add liveness/readyness probes to pods

oc status --suggest shows the following for some 3scale pods:

dc/backend-cron has no readiness probe to verify pods are ready to accept traffic or ensure deployment is successful.

dc/backend-cron has no liveness probe to verify pods are still running

dc/backend-worker has no readiness probe to verify pods are ready to accept traffic or ensure deployment is successful

dc/backend-worker has no liveness probe to verify pods are still running.

dc/system-sidekiq has no readiness probe to verify pods are ready to accept traffic or ensure deployment is successful.

dc/system-sidekiq has no liveness probe to verify pods are still running.

dc/system-sphinx has no readiness probe to verify pods are ready to accept traffic or ensure deployment is successful.

dc/zync-que has no readiness probe to verify pods are ready to accept traffic or ensure deployment is successful.

It would be good to have some probes so that pods are restarted in case they don't work properly.