Replace CP integer ID with a UUID.

This allows unique identification across saves. The front-end needs to
be able to differentiate the first carrier in game A and the first
carrier in game B, but because carriers (and other non-airfield CPs) are
assigned IDs sequentially, collisions were to be expected. The front-end
can't tell the difference between a reloaded game and a new turn, so we
need to ensure different IDs across games.

This is a handy cleanup anyway, since callers constructing CPs no longer
need to manually track the CP ID counter.

Fixes https://github.com/dcs-liberation/dcs_liberation/issues/2078.

client/src/components/controlpointslayer/ControlPointsLayer.tsx

@@ -9,7 +9,7 @@ export default function ControlPointsLayer() {
     <LayerGroup>
       {Object.values(controlPoints.controlPoints).map((controlPoint) => {
         return (
-          <ControlPoint key={controlPoint.name} controlPoint={controlPoint} />
+          <ControlPoint key={controlPoint.id} controlPoint={controlPoint} />
         );
       })}
     </LayerGroup>