Stops the conveyor for a tunnel.

Required permission: control:conveyor

Tell the server which company and tunnel to act on using the request headers.

The server first checks the conveyor's current state:

• If it is already stopped, there is nothing to do and the endpoint returns 200 OK.
• Otherwise the stop request is accepted and returns 202 Accepted. A 202 confirms the request was accepted — not that the conveyor has already come to a full stop.

To view the conveyor's current state, fetch the device heartbeat: GET /heartBeat/ and read the conveyour_state field (RUNNING, STOPPED, PAUSED, UNKNOWN, STARTING).