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

wpilibc/src/test/native/cpp/shuffleboard/SuppliedValueWidgetTest.cpp

@@ -97,7 +97,7 @@ TEST_F(SuppliedValueWidgetTest, AddBooleanArray) {
 }
 
 TEST_F(SuppliedValueWidgetTest, AddRaw) {
-  wpi::StringRef bytes = "\1\2\3";
+  std::string_view bytes = "\1\2\3";
   m_tab->AddRaw("Raw", [&bytes]() { return bytes; });
   auto entry = m_ntInst.inst.GetEntry("/Shuffleboard/Tab/Raw");