Use std::string_view and fmtlib across all libraries (#3402)

- Twine, StringRef, Format, and NativeFormatting have been removed
- Logging now uses fmtlib style formatting
- Nearly all uses of wpi::outs/errs have been replaced with fmt::print() or
std::puts()/std::fputs() (for unformatted strings).
- A wpi/fmt/raw_ostream.h header has been added to enable
fmt::print() with wpi::raw_ostream

wpimath/src/main/native/include/frc/spline/SplineParameterizer.h

@@ -33,8 +33,6 @@
 #include <utility>
 #include <vector>
 
-#include <wpi/Twine.h>
-
 #include "frc/spline/Spline.h"
 #include "units/angle.h"
 #include "units/curvature.h"

wpimath/src/main/native/include/frc/trajectory/TrajectoryUtil.h

@@ -5,9 +5,7 @@
 #pragma once
 
 #include <string>
-
-#include <wpi/StringRef.h>
-#include <wpi/Twine.h>
+#include <string_view>
 
 #include "frc/trajectory/Trajectory.h"
 
@@ -25,7 +23,7 @@ class TrajectoryUtil {
    * @return The interpolated state.
    */
   static void ToPathweaverJson(const Trajectory& trajectory,
-                               const wpi::Twine& path);
+                               std::string_view path);
   /**
    * Imports a Trajectory from a PathWeaver-style JSON file.
    *
@@ -33,7 +31,7 @@ class TrajectoryUtil {
    *
    * @return The trajectory represented by the file.
    */
-  static Trajectory FromPathweaverJson(const wpi::Twine& path);
+  static Trajectory FromPathweaverJson(std::string_view path);
 
   /**
    * Deserializes a Trajectory from PathWeaver-style JSON.
@@ -51,6 +49,6 @@ class TrajectoryUtil {
    *
    * @return the string containing the serialized JSON
    */
-  static Trajectory DeserializeTrajectory(wpi::StringRef json_str);
+  static Trajectory DeserializeTrajectory(std::string_view json_str);
 };
 }  // namespace frc