Increase the QPS and Burst value of the kubefed controller manager

Created by: iawia002

When I was debugging issue https://github.com/kubesphere/kubesphere/issues/4343, I found that the QPS and Burst values for the rest-client of the kubefed-controller-manager component were configured very low(5 and 10), causing the component to start very slowly:

Waited for due to client-side throttling, not priority and fairness

So I set it to a suitable value.

/cc @zryfish