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

wpiutil/src/main/native/include/wpi/Demangle.h

@@ -6,8 +6,7 @@
 #define WPIUTIL_WPI_DEMANGLE_H_
 
 #include <string>
-
-#include "wpi/Twine.h"
+#include <string_view>
 
 namespace wpi {
 
@@ -17,7 +16,7 @@ namespace wpi {
  * @param mangledSymbol the mangled symbol.
  * @return The demangled symbol, or mangledSymbol if demangling fails.
  */
-std::string Demangle(const Twine& mangledSymbol);
+std::string Demangle(std::string_view mangledSymbol);
 
 }  // namespace wpi