Build next NGINX image with NJS

[rikatz]

NJS provides an easy way of scripting for NGINX.

Some features from openresty and from external nginx modules can be replaced by njs scripts.

We should:

• Build the next NGINX image with NJS
• Analyze and map all the modules / modules features, and what can be replaced by some NJS script
• Make sure that there is no way a user can call njs from annotations

[k8s-ci-robot]

This issue is currently awaiting triage.

If Ingress contributors determines this is a relevant issue, they will accept it by applying the triage/accepted label and provide further guidance.

The triage/accepted label can be added by org members by writing /triage accepted in a comment.

Instructions for interacting with me using PR comments are available [here](https://git.k8s.io/community/contributors/guide/pull-requests.md). If you have questions or suggestions related to my behavior, please file an issue against the [kubernetes/test-infra](https://github.com/kubernetes/test-infra/issues/new?title=Prow%20issue:) repository.

[github-actions[bot]]

This is stale, but we won't close it automatically, just bare in mind the maintainers may be busy with other tasks and will reach your issue ASAP. If you have any question or request to prioritize this, please reach #ingress-nginx-dev on Kubernetes Slack.

[longwuyuan]

https://github.com/kubernetes/ingress-nginx/issues/12383