When deadman timer kicks in the motor node needs to ramp down, not just hard stop

[mjstn]

Hard stop due to deadman timer can and has been toppling robots in the field for deadman timer stops.

This is not an MCB issue and should be dealt with where logic for such things is above the raw MCB motor control.

This may mean the MCB deadman is set a bit longer then the motor node ramps in slowdown at the currently stated deadman timer interval.