feat: [receiver/k8scluster] Add optional k8s.container.status.waiting metric

[povilasv]

Description

Adds optional k8s.container.status.waiting metric, which tracks if container is in waiting state or not.

This is same exact thing what Kube State Metrics does with kube_pod_container_status_waiting.

Link to tracking issue

Fixes #32457

Testing

• added unit tests

Documentation

[TylerHelmuth]

I'd like to see this, but we need to pair it with a semconv PR to propose the metric: open-telemetry/semantic-conventions#1032

[povilasv]

@TylerHelmuth Wouldn't we want to first have implementation? In my opinion it would be great to test it in production and check whether it fits our needs / works the way we want to.

As if we add this first to semconv it will be set in stone forever? And in collector we have ways to deprecated and delete non useful metrics 🤔

[TylerHelmuth]

Yes but also k8s semantic convention stabilization stuff has just started and I want to be cautious about adding a metric that will quickly change. Reducing the amount of breaking changes (because there will be some) would be nice.