Add support for additional service labels to the helm chart

[cyril-s]

Proposed changes

Problem: It's not possible to add extra lables to the nginx gateway service (to select a particular CiliumLoadBalancerIPPool, for example).

Solution: Add support for adding extra labels to the nginx gateway service.

Testing: The following command renders a service manifest with an extra label lb-ip-pool=private as expected.

helm template ngf charts/nginx-gateway-fabric/ --set service.labels.lb-ip-pool=private -s templates/service.yaml

Checklist

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• I have read the CONTRIBUTING doc
• I have added tests that prove my fix is effective or that my feature works
• I have checked that all unit tests pass after adding my changes
• I have updated necessary documentation
• I have rebased my branch onto main
• I will ensure my PR is targeting the main branch and pulling from my branch from my own fork

Release notes

If this PR introduces a change that affects users and needs to be mentioned in the release notes,
please add a brief note that summarizes the change.

NONE

[nginx-bot]

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[github-actions]

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[cyril-s]

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

[sjberman]

Hi @cyril-s, thanks for the submission. We're going to hold off on this change right now because our architecture is changing in our next release (2.0) and there will be a different way to specify labels on the Service.

The control plane will provision an nginx data plane (including a Service) when you create your Gateway object (instead of the current architecture of a shared Pod between the control/data planes). On the Gateway object, you'll be able to set the infrastructure.labels field to propagate any labels to the nginx Service/Deployment objects that are provisioned. We'll have documentation around this as well.