`k8sattributes` processor semantic conventions transition

[ChrsMark]

Component(s)

processor/k8sattributes

Describe the issue you're reporting

Part of [k8s] Transition to stable semconv #43869

This is a placeholder issue to track the transition of this component to stable Semantic Conventions.

Probably this will happen after #35325, following a similar approach.

Cross-posting from open-telemetry/semantic-conventions#3120, the list of expected breaking changes:

1. container.image.tag is a future breaking since it will need to become container.image.tags to follow semconv
2. The k8s.*.labels/annotations.* breaking change is handled by k8sattr.labelsAnnotationsSingular.allow feature gate which's maturity is tracked at [k8sattributes] Mature k8sattr.labelsAnnotationsSingular.allow feature gate #44693. This was also tracked by Ensure that k8s labels and annotations follow SemConv #32440.
3. k8s.pod.hostname, k8s.pod.ip, k8s.pod.start_time are not defined as Semantic Conventions yet.

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[github-actions]

Pinging code owners:

• processor/k8sattributes: @dmitryax @fatsheep9146 @TylerHelmuth @ChrsMark

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