feat(conf): add label configuration option when Kong is exposed via ingress

[bergemalm]

What this PR does / why we need it:

Sometimes labels are used for filtering/configuring other resources. This PR adds support for adding custom labels to an ingress when Kong is exposed using an ingress controller.

Checklist

[Place an '[x]' (no spaces) in all applicable fields. Please remove unrelated fields.]

• PR is based off the current tip of the main branch.
• Changes are documented under the "Unreleased" header in CHANGELOG.md
• New or modified sections of values.yaml are documented in the README.md
• Commits follow the Kong commit message guidelines

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[pmalek]

Thanks! Do you mind adding this option to the README similarly how it's done for SVC.ingress.annotations?

[bergemalm]

Thanks! Do you mind adding this option to the README similarly how it's done for SVC.ingress.annotations?

I missed that one. Added! :)

[bergemalm]

Merge at will @pmalek ? :)