[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.

wpilibNewCommands/src/test/native/cpp/frc2/command/MecanumControllerCommandTest.cpp

@@ -2,10 +2,10 @@
 // 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.
 
-#include <frc2/Timer.h>
 #include <frc2/command/MecanumControllerCommand.h>
 #include <frc2/command/Subsystem.h>
 
+#include <frc/Timer.h>
 #include <frc/controller/PIDController.h>
 #include <frc/controller/ProfiledPIDController.h>
 #include <frc/geometry/Rotation2d.h>
@@ -27,7 +27,7 @@ class MecanumControllerCommandTest : public ::testing::Test {
                            units::inverse<units::squared<units::second>>>;
 
  protected:
-  frc2::Timer m_timer;
+  frc::Timer m_timer;
   frc::Rotation2d m_angle{0_rad};
 
   units::meters_per_second_t m_frontLeftSpeed = 0.0_mps;