Automatic merge from submit-queue

Add a simple cloud provider for e2e tests on kubemark

**What this PR does / why we need it**:
Adds a simplified cloud provider for kubemark. This enables us to add and
remove nodes and operate on nodegroups while running tests on kubemark.

This is needed to run scalability tests for cluster autoscaler on kubemark.
See https://github.com/kubernetes/autoscaler/blob/master/cluster-autoscaler/proposals/kubemark_integration.md

**Release note**:
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NONE
```