Baremetal support

[robertglonek]

This can be implemented fairly simply, but allowing a baremetal backend. The backend would take a configuration file which would define the cluster machines available (list of IPs, and ssh keys to access the machines). The baremetal backend would then proceed to support the required functions, except it would keep using the existing machines as defined as an actual cluster, instead of deploying new machines. Aside from cluster start and cluster stop everything else can be easily defined. Stopping and starting physical machines would probably be a bad idea.