Add "floating-ip" attribute to role definition

[smithfarm]

There is a use case for adding a "floating-ip" attribute in the role definition.

Currently, all nodes get a public IP address assigned from Amazon's pool. The assignment changes every time the node boots. When preparing a hands-on class/demo, there is a need to include in the class materials the IP address of the admin node, windows node, or whatever node(s), since it may be difficult or impossible for the student/delegate to find out this information.

The class materials typically need to be prepared in advance, yet the Delegate Clusters are spun up immediately prior to the class. Since the IP addresses are ephemeral, there is no way to know them in advance. Floating IPs would be a solution to this problem.