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/HttpUtil.inc

@@ -18,7 +18,7 @@ inline HttpPathRef HttpPath::drop_front(size_t n) const {
 template <typename T>
 HttpRequest::HttpRequest(const HttpLocation& loc, const T& extraParams)
     : host{loc.host}, port{loc.port} {
-  StringMap<StringRef> params;
+  StringMap<std::string_view> params;
   for (const auto& p : loc.params) {
     params.insert(std::make_pair(GetFirst(p), GetSecond(p)));
   }
@@ -30,7 +30,7 @@ HttpRequest::HttpRequest(const HttpLocation& loc, const T& extraParams)
 }
 
 template <typename T>
-void HttpRequest::SetPath(StringRef path_, const T& params) {
+void HttpRequest::SetPath(std::string_view path_, const T& params) {
   // Build location including query string
   raw_svector_ostream pathOs{path};
   pathOs << path_;