Wafmc 13048 doc offline solution ap signatures

[Y-Klughaupt]

Proposed changes

Added suggested offline solution for users who don’t want to download the security update pkgs from nginx repo.

Checklist

Before sharing this pull request, I completed the following checklist:

• I read the Contributing guidelines
• My branch adheres to the Git conventions
• My content changes adhere to the F5 NGINX Documentation style guide
• If my changes involve potentially sensitive information¹, I have assessed the possible impact
• I have waited to ensure my changes pass tests, and addressed any discovered issues

Footnotes

1. Potentially sensitive information includes personally identify information (PII), authentication credentials, and live URLs. Refer to the style guide for guidance about placeholder content. ↩

[github-actions]

✅ All required contributors have signed the F5 CLA for this PR. Thank you!
_{Posted by the CLA Assistant Lite bot.}

[mjang]

@Y-Klughaupt , can you "sign" the CLA, as requested in #1098 (comment)

[Y-Klughaupt]

I have hereby read the F5 CLA and agree to its terms