Remove cgroup driver configuration from e2e test infra

[rajnkamr]

No need to explicitly set cgroupDriver in kubelet configuration.
The kubelet will pick the correct driver automatically, avoiding misconfiguration.

[antoninbas]

@rajnkamr are you still using the Vagrantfile / Ansible playbook? Because I was considering removing it from the repo

[rajnkamr]

@antoninbas
We used Vagrantfile / Ansible playbook few months back due to some issues with kind.
Went through some of discussions on it recently, I think plan is to migrate it to downstream CI .

@XinShuYang can confirm on migration.
IMO, we will also have to clean up documentation then.
https://github.com/antrea-io/antrea/tree/main/test/e2e#creating-the-test-kubernetes-cluster-with-vagrant

In that case, will close this PR, will open the PR in ci repo after migration.

[XinShuYang]

@XinShuYang can confirm on migration.

For the testbed deployment scripts, I have migrated the target repo to ensure future antrea code changes won't affect their deployment.