deploy/ci: Add dummy node

Remove all roles from DEFAULT section in setups.conf. This way each
setup has only the roles/nodes that includes in the corresponding
section. Since currently the Context() class expects to find all
roles in each setup (db, mq, etc.) we have to introduce a dummy node
that eventually should not be used.

Set DEFAULT_NODE and DEFAULT_CLUSTER to None. One should only
specify the desired setup (with --setup option) and the nodes, and
clusters should derive from it.

Signed-off-by: Dimitris Aragiorgis <dimara@grnet.gr>
deploy: Print ssh/vnc info after vcluster command

Signed-off-by: Dimitris Aragiorgis <dimara@grnet.gr>
deploy/ci: Remove dummy password in nodes.conf

Since snf-deploy image does passwd -d root the nodes will have
empty password.

Set UsePAM no and PermitEmptyPasswords yes in sshd_config in
vcluster image.

Signed-off-by: Dimitris Aragiorgis <dimara@grnet.gr>