Show os version and release channel

[jareddlc]

We should add os version and release channel information about the host machine, into the machines view.

Currently we are using fleetctl to grab machine info using list-machines, but the information we want is not present. We need to find a solution into getting the information we want.

[jareddlc]

Contacted Coreos with a feature request to add the data in fleetctl list-machines coreos/fleet#1228