Remove cpu limits from the best practice policy

[realshuting]

CPU limits are non-intuitive and do not work as most users expect. See:

https://www.reddit.com/r/kubernetes/comments/all1vg/on_kubernetes_cpu_limits/

kubernetes/kubernetes#51135

https://medium.com/@betz.mark/understanding-resource-limits-in-kubernetes-cpu-time-9eff74d3161b

https://learnk8s.io/production-best-practices

https://stackoverflow.com/questions/54099425/pod-cpu-throttling

We need to remove cpu limits in this best practice policy.