Resolve "See if we can prevent cronjob from spawning if wordpress pod is not ready"

Closes #53 (closed)

I couldn't stop the pod from spawning, so instead I check if the curl request can connect at all. If it can't we assume the service is not up (which should lead to other monitoring errors than this pod failing). We won't raise an error at that time.

I also found out that our cron script returns HTTP 200 when the secret is invalid, so I explicitly check that the script does not generate any output and returns a 200 code (it would say invalid secret string if the secret is not good).