Update aws nlb manifests installation

[bjee19]

There is no longer an aws-nlb deploy.yaml file, so we need to update the manifests installation and give some information on setting annotations in the Gateway.

Problem: There is no longer an aws-nlb deploy.yaml file, so we need to update documentation.

Solution: Update the documentation and give information on setting annotations on the Gateway.

Testing: Checked with make watch

Related with: nginx/nginx-gateway-fabric#3362

Closes

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• If applicable, I have updated README.md and CHANGELOG.md

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