Kustomize documented as only for example usage

[shaneutt]

@kong/team-k8s intention for the kustomize deployments present in the repository are for example usage only, with the Helm Chart being the intended deployment and upgrade methods for production use cases.

As such, the purpose of this task is to ensure the documentation for the KIC in docs.konghq.com reflects this properly with warnings and notes that Helm should be used when deploying to prod.

Acceptance Criteria

• anywhere kustomize is used in the docs should have a disclaimer added that kustomize is not meant for prod, and helm should be used when deploying to production

[shaneutt]

This is resolved in that the documentation is written, but there is a follow up for the final merge to main: #1719