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

hal/src/main/native/cpp/jni/HALUtil.h

@@ -8,7 +8,7 @@
 #include <jni.h>
 #include <stdint.h>
 
-#include <wpi/StringRef.h>
+#include <string_view>
 
 struct HAL_MatchInfo;
 struct HAL_Value;
@@ -51,7 +51,7 @@ inline bool CheckCANStatus(JNIEnv* env, int32_t status, int32_t message_id) {
   return status == 0;
 }
 
-void ThrowIllegalArgumentException(JNIEnv* env, wpi::StringRef msg);
+void ThrowIllegalArgumentException(JNIEnv* env, std::string_view msg);
 void ThrowBoundaryException(JNIEnv* env, double value, double lower,
                             double upper);