Support the Eviction api

[svenwiltink]

When draining a node it is useful to evict the pods on a node 1 by 1 using api initiated evictions. This is useful because those requests respect the pod disruption budgets. The api is a little funky because it talks to the /api/v1/namespaces/<namespace>/pods/<pod>/eviction endpoint while the resource is policy/v1.

I am working on an implementation in my fork: #454