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

glass/src/libnt/native/cpp/NTGyro.cpp

@@ -4,17 +4,20 @@
 
 #include "glass/networktables/NTGyro.h"
 
+#include <fmt/format.h>
+#include <wpi/StringExtras.h>
+
 using namespace glass;
 
-NTGyroModel::NTGyroModel(wpi::StringRef path)
+NTGyroModel::NTGyroModel(std::string_view path)
     : NTGyroModel(nt::GetDefaultInstance(), path) {}
 
-NTGyroModel::NTGyroModel(NT_Inst instance, wpi::StringRef path)
+NTGyroModel::NTGyroModel(NT_Inst instance, std::string_view path)
     : m_nt(instance),
-      m_angle(m_nt.GetEntry(path + "/Value")),
-      m_name(m_nt.GetEntry(path + "/.name")),
-      m_angleData("NT_Gyro:" + path),
-      m_nameValue(path.rsplit('/').second) {
+      m_angle(m_nt.GetEntry(fmt::format("{}/Value", path))),
+      m_name(m_nt.GetEntry(fmt::format("{}/.name", path))),
+      m_angleData(fmt::format("NT_Gyro:{}", path)),
+      m_nameValue(wpi::rsplit(path, '/').second) {
   m_nt.AddListener(m_angle);
   m_nt.AddListener(m_name);
 }