Add crond log level environment variable

[MarcelCoding]

I couldn't find any documentation regarding the second cron entry point, I just found it in the stack.yaml. I added an environment variable to configure the log level, the default case is logging every minute about 3 lines and I found that quite much - not everyone can configure it how he wants it. The default is 0 just as before.

Signed-off-by: Marcel [email protected]