illumos gate

With the advent of the vmm reservoir, it would be nice to be able to restrict allocations from said reservoir (both normal and "transient") by non-global-zone bhyve consumers. In addition to the vmm instance memory restrictions, it would also make sense to be able to control the maximum number of vCPUs a zone is able to run. That would allow us to lift the existing "only one vmm instance per zone" limit in favor of something which leaves those decisions up to the zone itself.