Support NGINX Debug Mode when Provisioning Data Plane

[mpstefan]

As a user of NGF
I want to be able to provision the NGINX instances for a Gateway or all of NGF in debug mode
So that I can debug NGINX when I encounter issues with the data plane.

Acceptance

• When the user specifies debug mode for a Gateway or the GatewayClass via CRD, the NGINX instances belonging to that scope will have their debug mode enabled.
• NGF documentation is updated to show how to enabled debug mode for NGINX instances:
  • Troubleshooting doc
  • Data Plane Configuration
  • Any other area that may include a reference to Debug Mode