Create guide: Use NGINX One Config Sync Groups to apply `license.jwt` across instances (R33 prep)

[travisamartin]

Overview
NGINX Plus R33 introduces stricter license enforcement that requires a valid license.jwt file on all running instances. Many customers are hesitant to upgrade due to the added overhead in distributing and managing these licenses.

This issue tracks the creation of a customer-facing, standalone guide that shows how to use NGINX One Config Sync Groups (CSGs) and the Config Editor to apply the license.jwt file across multiple instances. The guide will be based on Lab 8 from the SE training, with Docker setup instructions removed or minimized.

Purpose
This use case:

• Provides a clear solution for preparing environments to upgrade to R33
• Highlights a concrete, operational benefit of using NGINX One
• Helps reduce upgrade friction and surface the value of N1

Deliverables

• Markdown doc with:
  • Clear, step-by-step instructions to apply license.jwt using CSGs and the Config Editor
  • Description of prerequisites and expected outcomes
  • Link to About Subscription Licenses
  • Troubleshooting tips and verification steps
• Reusable for inclusion in onboarding and upgrade documentation
• Shared as a reference in R33 comms and N1 enablement efforts

Audience
Enterprise or infrastructure teams running multiple NGINX Plus instances—especially those using or evaluating NGINX One.

Impact

• Reduces upgrade anxiety and complexity
• Promotes NGINX One through real-world value
• Improves overall customer experience with licensing and config management