world: add ejectPiece

app/src/main/java/chess/view/DDDrender/world/World.java

@@ -45,6 +45,13 @@ public class World implements Closeable{
 		setPieceCoords(null, move.getStart());
 	}
 
+	public void ejectPiece(Coordinate coordinate) {
+		PieceEntity entity = getPiece(coordinate);
+		assert entity != null;
+		this.entites.remove(entity);
+		setPieceCoords(null, coordinate);
+	}
+
 	public PieceEntity getPiece(Coordinate coordinate) {
 		return pieces[coordinate.toIndex()];
 	}