[wpilibj] Allow passing DS Instance to Robot and OpModes (#8626)

Some discussion with the tech team showed that there were some real
advantages to being able to pass a 2nd type. It allows separating the DS
and Robot. Additionally, we can make the DriverStationBase class
actually usable instead of the existing DriverStation class which is
impossible to handle in intellisense because it has too much.

This won't fully be doable in C++, but we will need to implement
something similar in python.

wpilibj/src/main/java/org/wpilib/driverstation/UserControls.java

@@ -0,0 +1,15 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+package org.wpilib.driverstation;
+
+/**
+ * An interface representing user controls such as gamepads or joysticks. If your main robot class
+ * has a UserControlsInstance attribute with a class implementing this interface, the constructor is
+ * able to receive an instance of that class. Additionally, any OpModes can also receive that same
+ * instance.
+ *
+ * <p>The implementation of this class must have a default constructor
+ */
+public interface UserControls {}