feat: add json logging for nginx / nginx plus ic

[qdzlug]

Is your feature request related to a problem? Please describe. We currently use a custom logging format specifically to address issues that we were seeing with Kibana - the default NGINX IC (upstream) uses a different logging format than the NGINX, Inc IC (both Plus and OSS). Since we are now looking to move away from Elastic to another logging solution it probably makes sense to go with a different logging format and json makes the most sense.

Fortunately, we have this already written in another example here.

Describe the solution you'd like This change will update the nginx configuration (values for helm) to use this logging format.

Describe alternatives you've considered None.

Additional context n/a