Systemd, Launchd, & Service Control Manager

### Feature Idea

Since ComfyUI will be periodically restarted, it might make sense to manage restarting in a platform universal way.

Windows - Service Control Manager
MacOS - launchd
Linux - systemd

These are system-level init/management services that support features such as:
- automatic startup & shutdown with the OS
- watchdog restarts
- restart on demand

For instance, when you click the restart button in ComfyUI-Manager, it could signal the appropriate service manager for that platform.

If this is something you think would be helpful to the project, express some support here, and I'll prepare a POC.

### Existing Solutions

I already run ComfyUI via systemd, on my machine.

### Other

_No response_