[wpilib] Remove PIDController, PIDOutput, PIDSource

Move them to the old commands vendordep so that PIDCommand and PIDSubsystem
continue to work.

This also removes Filter and LinearDigitalFilter.

wpilibc/src/main/native/include/frc/AnalogInput.h

@@ -9,7 +9,6 @@
 #include <hal/Types.h>
 
 #include "frc/ErrorBase.h"
-#include "frc/PIDSource.h"
 #include "frc/smartdashboard/Sendable.h"
 #include "frc/smartdashboard/SendableHelper.h"
 
@@ -32,7 +31,6 @@ class DMASample;
  * stable values.
  */
 class AnalogInput : public ErrorBase,
-                    public PIDSource,
                     public Sendable,
                     public SendableHelper<AnalogInput> {
   friend class AnalogTrigger;
@@ -280,13 +278,6 @@ class AnalogInput : public ErrorBase,
    */
   static double GetSampleRate();
 
-  /**
-   * Get the Average value for the PID Source base object.
-   *
-   * @return The average voltage.
-   */
-  double PIDGet() override;
-
   /**
    * Indicates this input is used by a simulated device.
    *