Resolve WES-99 "Cc refactor"

Assets/Common/Scripts/BackButton.cs

@@ -0,0 +1,15 @@
+using UnityEngine;
+
+/// <summary>
+/// Script managing the default 'back'-button action
+/// </summary>
+public class BackButton : MonoBehaviour
+{
+    /// <summary>
+    /// The default 'back'-button action: go back to the previous scene
+    /// </summary>
+    public void Back()
+    {
+        SystemController.GetInstance().BackToPreviousScene();
+    }
+}