Mark local offloaded pods as NotReady when virtual-node is not ready (i.e. remote cluster failure)

[fra98]

Description

This PR changes the virtual-kubelet logic to mark local offloaded pods as NotReady when the remote cluster has a failure (i.e., the liqo virtual node has the Ready condition set to False or Unknown).
In summary, it sets the Ready pod condition to False on all pods scheduled on a NotReady virtual node.

Implementation

• A new controller in the liqo-controller-manager enforces the presence/absence of a custom label on
  local offloaded pods. The presence of the label indicates that the status of the offloaded pod can be managed/updated by the local cluster and can't currently be reflected/updated from the remote cluster (likely due to a remote cluster failure).
• The virtual-kubelet makes sure that the Ready conditions of the local offloaded pods are set to False if the label is present.

Motivation

We mark pods as NotReady because the Kubernetes node controller skips this update (likely due to a bug). This is necessary to prevent services redirecting traffic to not ready pods (since the endpointslice controller keeps in sync the endpointslice Ready condition with the associated pod Ready condition).

How Has This Been Tested?

• Locally
• Unit tests
• e2e tests

[adamjensenbot]

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[fra98]

/test

[fra98]

/rebase test=true

[fra98]

/merge