Config YAML should set location of Kubernetes manifest files

[lizrice]

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At the moment the config.yaml file has a confs section with a series of candidate file names and locations for the pod configuration for each component. If these components are configured through static pod manifest files, they will all be in the same directory. We could simplify the config.yaml file by having that directory configured once (or auto-detected by looking at the kubelet's configuration)

If we know what the static pod config location is, that would allow us to auto-detect which components are supposed to be running (e.g. is etcd managed by Kubernetes? Not if there isn't an etcd static pod manifest file. That would help wtih issues like #632

See https://kubernetes.io/docs/tasks/configure-pod-container/static-pod/