[Idea]: Document how to install NIC using its Helm chart in airgapped environment

[fabriziofiorucci]

What is your idea for improving documentation?

Here https://docs.nginx.com/nginx-ingress-controller/install/helm/#install-the-helm-chart-from-source we should mention/recommend using --skip-schema-validation to work in airgapped environments.
This Helm flag requires Helm 3.16

Which product or products does this idea relate to?

NGINX Ingress Controller

Does this idea relate to other issues?

No response

Are there alternative ideas for improving the same topic?

No response

Any additional information

No response

[ADubhlaoich]

I think airgapped deployments will be their own document.

I investigated some of the steps around this for WAF last quarter: when I work on this for NGINX Ingress Controller, I should also be able to clarify steps for F5 WAF for NGINX, too.