Detect when controller loses connection to API server

[linki]

We see this in the logs when API servers are rolled (presumably):

W0304 09:48:56.883806       1 reflector.go:340] pkg/mod/k8s.io/client-go@v0.0.0-20191202165906-e3970fe37d8a/tools/cache/reflector.go:108: watch of *v1.StackSet ended with: an error on the server ("unable to decode an event from the watch stream: context deadline exceeded (Client.Timeout or context cancellation while reading body)") has prevented the request from succeeding

This currently wouldn't be catched by the previous PRs #204 and #203