Moved the signalbox icons

*Moved the signalbox icons to /public/assets/signalboxes/

src/components/map/object-renderers/SignalBoxRenderer.js

@@ -15,7 +15,7 @@ export default function SignalBoxRenderer(props) {
     <g className="signalbox" transform={`translate(${x}, ${y}) rotate(${rot}) `}>
       <g className="signalbox-icon" transform={`translate(-4.725, -4.725)`}>
           <ReactSVG
-              src={`/assets/${object.def.icon}`}
+              src={`/assets/signalboxes/${object.def.icon}`}
               wrapper='svg'
 
               beforeInjection={(svg) => {