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/CANJNI.cpp

@@ -6,9 +6,7 @@
 
 #include <cassert>
 
-#include <wpi/SmallString.h>
 #include <wpi/jni_util.h>
-#include <wpi/raw_ostream.h>
 
 #include "HALUtil.h"
 #include "edu_wpi_first_hal_can_CANJNI.h"
@@ -65,8 +63,8 @@ Java_edu_wpi_first_hal_can_CANJNI_FRCNetCommCANSessionMuxReceiveMessage
     return nullptr;
   }
   return MakeJByteArray(env,
-                        wpi::StringRef{reinterpret_cast<const char*>(buffer),
-                                       static_cast<size_t>(dataSize)});
+                        std::string_view{reinterpret_cast<const char*>(buffer),
+                                         static_cast<size_t>(dataSize)});
 }
 
 /*