feat: restart the firewall (reboot_host)

netOrk asks a driver for reboot_host before it offers a restart, and the
OPNsense driver had none, so a firewall could not be restarted from netOrk
(netOrk #637). reboot_host asks the firmware API (POST
/api/core/firmware/reboot); a refusal raises.

napalm_opnsense/opnsense.py

@@ -2050,6 +2050,16 @@ class OPNsenseDriver(OPNsensePingMixin, FirewallDriver):
             "output": f"The update check did not finish within {_REFRESH_POLLS * _REFRESH_INTERVAL} s",
         }
 
+    def reboot_host(self) -> None:
+        """Restart the firewall through its firmware API (``HostRebootMixin``).
+
+        :raises RuntimeError: when the API refuses the request.
+        """
+        try:
+            self._post("/api/core/firmware/reboot")
+        except Exception as exc:
+            raise RuntimeError(f"The firewall refused to reboot: {exc}") from exc
+
     def get_host_status(self) -> dict[str, Any]:
         """Whether the firewall needs a reboot to finish an update; it does not
         patch itself as far as netOrk can tell."""