[processor/k8sattributes] Sync k8s workload labels and annotations attributes to match semconv

[odubajDT]

Component(s)

processor/k8sattributes

Describe the issue you're reporting

Resource attributes of k8s workloads which are injected from labels and annotations have a wrong key format k8s.<workload>.labels.<label-key> and k8s.<workload>.annotations.<annotation-key>.

According to the latest semconv (list of open and closed issues), the processor should be aligned to the semconv once all of them get merged.

The resulting keys should be:

k8s.<workload>.label.<label-key>
k8s.<workload>.annotation.<annotation-key>

The change should be hidden behind a feature gate to allow a smooth transition for the users, since it will result in a breaking change.

[github-actions]

Pinging code owners:

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

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