add default structure for AntAgent

src/main/java/core/DiscreteAction.java

@@ -7,6 +7,10 @@ public class DiscreteAction<A extends Enum> implements Action{
         this.action = action;
     }
 
+    public A getValue(){
+        return action;
+    }
+
     @Override
     public int getIndex(){
        return action.ordinal();

src/main/java/core/StepResult.java

@@ -8,7 +8,7 @@ import lombok.Setter;
 @Setter
 @AllArgsConstructor
 public class StepResult {
-    private Observation observation;
+    private State observation;
     private double reward;
     private boolean done;
     private String info;