[test] support cluster-api style rolling replacement upgrade

What would you like to be added?

Currently our e2e framework supports in-place upgrade. We just replace the binary, and reuse the existing data.

https://github.com/etcd-io/etcd/blob/30452ab110473eda5f60bdb301c046194a154e91/tests/framework/e2e/downgrade.go#L131

However, the cluster-api/Kubeadm upgrades Kubernetes cluster in a rolling replacement approach,

• add a new learner first;
• promote it later
• remove an old node
• repeat the above steps until all nodes are replaced.

The key difference is the new member(learner) gets started without local data, so it may receive a snapshot from the leader.

We should update our e2e test framework to support both upgrade approaches,

• rolling in-place upgrade
• rolling replacement upgrade

Why is this needed?

To improve test coverage.