Analogous to the shutdown operation on the standalone server, but shuts down the HC.
We need to think through the reasonable variants. A full shutdown of the ProcessController and all child processes is one. Another is a restart of the HC, leaving all servers running. A third is a shutdown of all servers, followed by a restart of the HC which would bring up auto-start servers.
A shutdown of the HC but not the PC is not allowed; the PC will always ensure there is an HC.