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/athena/PWM.cpp

@@ -4,11 +4,11 @@
 
 #include "hal/PWM.h"
 
+#include <algorithm>
 #include <cmath>
+#include <cstdio>
 #include <thread>
 
-#include <wpi/raw_ostream.h>
-
 #include "ConstantsInternal.h"
 #include "DigitalInternal.h"
 #include "HALInitializer.h"
@@ -138,8 +138,8 @@ void HAL_FreePWMPort(HAL_DigitalHandle pwmPortHandle, int32_t* status) {
   while (port.use_count() != 1) {
     auto current = hal::fpga_clock::now();
     if (start + std::chrono::seconds(1) < current) {
-      wpi::outs() << "PWM handle free timeout\n";
-      wpi::outs().flush();
+      std::puts("PWM handle free timeout");
+      std::fflush(stdout);
       break;
     }
     std::this_thread::yield();