Add support for creating baremetal flavors

To improve the support for heterogenous nodes, add support for
deleting existing flavors in Nova, and creating baremetal flavors
that describe all nodes, allowing the caller to also override which
flavors are created. A setup-flavors CLI tool is provided for ease
of use with -incubator.

Change-Id: Ie139304016ef7553a46d9708be4281cc6afccb07
Merge "Add support for creating baremetal flavors"