Use ToBeDeletedByClusterAutoscaler Taint to improve load balancing during machine terminations

[dergeberl]

What this PR does / why we need it:

If a machine is deleted the it is possible that the load balancer do not know yet that the node is not available anymore. This results eventually in unsuccessful new connections as the node where the load balancer is forwarding the traffic is not existing anymore.

There are 2 ways a load balancer gets informed: 1. Via a reconcile of the load balancer in the cloud-provider package or the kube-proxy health check. Unfortunately the "drain" or conditions set by the MCM dose not trigger a reconcile or the health check to fail.

The ToBeDeletedByClusterAutoscaler Taint is used in both cloud-provider and kube-proxy, therefore we want to add this Taint to improve the load balancing during machine terminations.

This is new step is added between Initiate node drain/Delete Volume Attachments and Initiate VM deletion with one additional ShortRetry (5s) to give the cloud-provider and kube-proxy time to react before removing the server.

CC: @kon-angelo

Which issue(s) this PR fixes:
Fixes #

Special notes for your reviewer:

Release note:

Use `ToBeDeletedByClusterAutoscaler` Taint to improve load balancing during machine terminations.