FreeBSD/bhyve: Use vm<PID> for VM name, VM cleanup change
FreeBSD/bhyve: Use vm<PID> for VM name, VM cleanup change

- Address #141 by using VM<PID> for the bhyve VM name.
- Rather than blowing away an existing bhyve VM of the same name each time we
run, move the cleanup to be done in solo5-run-virtio.sh SIGINT/SIGTERM processing.

Weichen81/solo5,djwillia/solo5,mato/solo5,Solo5/solo5,Weichen81/solo5,mato/solo5,Weichen81/solo5,mato/solo5,djwillia/solo5,djwillia/solo5,Solo5/solo5