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/MockActuatorSendable.cpp

@@ -6,10 +6,12 @@
 
 #include "frc/smartdashboard/SendableRegistry.h"
 
+using namespace frc;
+
 MockActuatorSendable::MockActuatorSendable(std::string_view name) {
-  frc::SendableRegistry::GetInstance().Add(this, name);
+  SendableRegistry::GetInstance().Add(this, name);
 }
 
-void MockActuatorSendable::InitSendable(frc::SendableBuilder& builder) {
+void MockActuatorSendable::InitSendable(SendableBuilder& builder) {
   builder.SetActuator(true);
 }