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/simulation/AccelerometerSimTest.cpp

@@ -22,7 +22,7 @@ TEST(AcclerometerSimTests, TestActiveCallback) {
   bool lastValue = false;
 
   auto cb = sim.RegisterActiveCallback(
-      [&](wpi::StringRef name, const HAL_Value* value) {
+      [&](std::string_view name, const HAL_Value* value) {
         wasTriggered = true;
         lastValue = value->data.v_boolean;
       },