Add component menues for some sensors and actuators. (#5001)

com.unity.ml-agents.extensions/Runtime/Input/InputActuatorComponent.cs

     /// <see cref="InputActionActuator"/>s.
     /// </summary>
     [RequireComponent(typeof(PlayerInput), typeof(IInputActionAssetProvider))]
+    [AddComponentMenu("ML Agents/Input Actuator", (int)MenuGroup.Actuators)]
     public class InputActuatorComponent : ActuatorComponent
     {
         InputActionAsset m_InputAsset;
             }
 
             var inputControlScheme = new InputControlScheme(
-                 mlAgentsControlSchemeName,
+                mlAgentsControlSchemeName,
                 deviceRequirements);
 
             return inputControlScheme;
                     var builder = new InputControlLayout.Builder()
                         .WithName(layoutName)
                         .WithFormat(mlAgentsLayoutFormat);
-                    for(var i = 0; i < defaultMap.actions.Count; i++)
+                    for (var i = 0; i < defaultMap.actions.Count; i++)
                     {
                         var action = defaultMap.actions[i];
                         builder.AddControl(action.name)
-
                 }, layoutName);
             }
         }

com.unity.ml-agents.extensions/Runtime/Match3/Match3ActuatorComponent.cs

     /// <summary>
     /// Actuator component for a Match3 game. Generates a Match3Actuator at runtime.
     /// </summary>
+    [AddComponentMenu("ML Agents/Match 3 Actuator", (int)MenuGroup.Actuators)]
     public class Match3ActuatorComponent : ActuatorComponent
     {
         /// <summary>

com.unity.ml-agents.extensions/Runtime/Match3/Match3SensorComponent.cs

 using Unity.MLAgents.Sensors;
+using UnityEngine;
 
 namespace Unity.MLAgents.Extensions.Match3
 {
+    [AddComponentMenu("ML Agents/Match 3 Sensor", (int)MenuGroup.Sensors)]
     public class Match3SensorComponent : SensorComponent
     {
         /// <summary>

com.unity.ml-agents.extensions/Runtime/Sensors/GridSensor.cs

     /// <summary>
     /// Grid-based sensor.
     /// </summary>
+    [AddComponentMenu("ML Agents/Grid Sensor", (int)MenuGroup.Sensors)]
     public class GridSensor : SensorComponent, ISensor, IBuiltInSensor
     {
         /// <summary>
         {
             return BuiltInSensorType.GridSensor;
         }
-
 
         /// <summary>
         /// GetCompressedObservation - Calls Perceive then puts the data stored on the perception buffer

com.unity.ml-agents/Runtime/Constants.cs

     internal enum MenuGroup
     {
         Default = 0,
-        Sensors = 50
+        Sensors = 50,
+        Actuators = 100
     }
 }