[wpilibc] Transition C++ classes to units::second_t (#3396)

A lot of these are breaking changes. frc::Timer was replaced with the
contents of frc2::Timer. The others were in-place argument changes or
removing deprecated non-unit overloads.

wpilibcExamples/src/main/cpp/examples/SimpleDifferentialDriveSimulation/cpp/Robot.cpp

@@ -4,10 +4,10 @@
 
 #include <frc/SlewRateLimiter.h>
 #include <frc/TimedRobot.h>
+#include <frc/Timer.h>
 #include <frc/XboxController.h>
 #include <frc/controller/RamseteController.h>
 #include <frc/trajectory/TrajectoryGenerator.h>
-#include <frc2/Timer.h>
 
 #include "Drivetrain.h"
 
@@ -69,7 +69,7 @@ class Robot : public frc::TimedRobot {
   Drivetrain m_drive;
   frc::Trajectory m_trajectory;
   frc::RamseteController m_ramsete;
-  frc2::Timer m_timer;
+  frc::Timer m_timer;
 };
 
 #ifndef RUNNING_FRC_TESTS