[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/cpp/AnalogAccelerometer.cpp

@@ -48,10 +48,6 @@ void AnalogAccelerometer::SetZero(double zero) {
   m_zeroGVoltage = zero;
 }
 
-double AnalogAccelerometer::PIDGet() {
-  return GetAcceleration();
-}
-
 void AnalogAccelerometer::InitSendable(SendableBuilder& builder) {
   builder.SetSmartDashboardType("Accelerometer");
   builder.AddDoubleProperty(