This adds the Scheduler Hints step to the angular Launch Instance
workflow and allows specifying arbitrary hints when launching an
instance. It also displays available hints from the glance metadata
definitions catalog OS::Nova::Server namespace that use the
"scheduler_hints" properties target.
Implements: blueprint add-scheduler-hints
Change-Id: Ic33c31e645f45b7a4cbdf13e9a115c96399d5e32