Add node test functionality to ciao-deploy

[kaccardi]

It would be nice for a cloud admin to be able to verify the functionality of each of the nodes in their new ciao cluster by running a simple test "ciao-deploy verify-nodes" or something. this test could launch a VM and a container workload on each node and confirm that the launch was successful. It could also confirm network functionality between nodes. This functionality is dependent on #1462, and #1484