Fix VM stop
On occasion bhyve freezes while maxing out CPU on one of the threads (seems to be a VirtIO issue without further diagnosis). At this point I need to kill the VM, but the "Stop" button doesn't seem to be able to do this like it does in Corral. Instead, it seems to just send the ACPI Shutdown request and that's it, and I have to kill -9 the bhyve process to actually shut it down.
I'd like to see the State to be "Stopping" and if the user clicks the Stop button once again, a kill command should be issued.