enter replicasets from deployments

[rudrakhp]

Fixes #2951

Today on entering a deployment, pods associated with it are listed. Changed behaviour to list replicasets instead. Entering replicaset will list the related pods.

Ran make build && ./execs/k9s on a test cluster to validate behaviour.

[dor1202]

@rudrakhp Nice!
I don't think i can review the code, so i will keep it for @derailed 😄 .
IMO, you're right that the replicaset makes more sense on enter press than the pod list. But, we should keep the pod behavior in a different shortcut (like P key if not used) and not removing it. I'm sure it's being used.

Side note, in any case we need to update the docs on the new logic

[rudrakhp]

I think the deployment --> replicaset --> pods flow is what everyone needs. I don't see a scenario where someone might need a strict deployment --> pods flow. Technically as well, it is replicasets that are associated with deployments and not pods. I will let @derailed pitch in regarding this along with his review, will add a shortcut then if required.

[derailed]

@rudrakhp Thank you for this PR! Tho technically this is correct, I don't think we should alter the current behavior as this was a conscious decision to get to the pertinent information quickly aka show me the latest incarnation of the pods associated with this deployment.
That said, I think it makes sense to nav dp->rs so users can see the various versions at stake.