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/main/native/cpp/smartdashboard/FieldObject2d.cpp

@@ -114,9 +114,9 @@ void FieldObject2d::UpdateEntry(bool setDefault) {
       p += 8;
     }
     if (setDefault) {
-      m_entry.SetDefaultRaw(wpi::StringRef{arr.data(), arr.size()});
+      m_entry.SetDefaultRaw({arr.data(), arr.size()});
     } else {
-      m_entry.ForceSetRaw(wpi::StringRef{arr.data(), arr.size()});
+      m_entry.ForceSetRaw({arr.data(), arr.size()});
     }
   }
 }
@@ -144,7 +144,7 @@ void FieldObject2d::UpdateFromEntry() const {
     }
   } else if (val->IsRaw()) {
     // treat it simply as an array of doubles
-    wpi::StringRef data = val->GetRaw();
+    std::string_view data = val->GetRaw();
 
     // must be triples of doubles
     auto size = data.size();
@@ -152,7 +152,7 @@ void FieldObject2d::UpdateFromEntry() const {
       return;
     }
     m_poses.resize(size / (3 * 8));
-    const char* p = data.begin();
+    const char* p = data.data();
     for (size_t i = 0; i < size / (3 * 8); ++i) {
       double x = wpi::BitsToDouble(
           wpi::support::endian::readNext<uint64_t, wpi::support::big,