Control plane logging configuration doc

[pleshakov]

Write a doc about logging configuration for control plane (for the user).

Include:

• log levels
• log format
• how critical errors (when control plane terminates) are logged
• how to change logging configuration.

[miledxz]

@kate-osborn I can pick this one if you are okey with that ?

[kate-osborn]

Hey @miledxz,

I don't think we are ready to complete this issue since we don't support setting log format and we already have a doc on log level.

I just cleaned up our good-first-issues list: https://github.com/nginx/nginx-gateway-fabric/issues?q=is%3Aissue%20state%3Aopen%20label%3A%22good%20first%20issue%22.

Any of those issues would be great to pick up 🙂

[miledxz]

thank you @kate-osborn !