Get Calico ippool by CR instead of Calico APIServer

[AllenXu93]

Now use ProjectcalicoV3 to retrieve calico IPPool, which is not stable because not every Calico cluster deploy Calico APIServer.

kubeskoop/pkg/skoop/plugin/calico.go

Line 254 in 6c4d36f

ippools, err := client.ProjectcalicoV3().IPPools().List(context.TODO(), metav1.ListOptions{})

We can use Ippool CR directly.