C++17ification.

C++17ification!

- Filesystem interaction now uses std::filesystem::path.
- Usage of const char*, std::string have been changed to
  std::string_view where appropriate.
- Usage of printf-style functions changed to use fmt.

src/xenia/cpu/ppc/ppc_opcode_info.cc

@@ -28,7 +28,7 @@ bool DisasmPPC(uint32_t address, uint32_t code, StringBuffer* str) {
     d.code = code;
     disasm_info.disasm(d, str);
   } else {
-    str->AppendFormat("%-8s", disasm_info.name);
+    str->AppendFormat("{:<8}", disasm_info.name);
   }
   return true;
 }