Logging: Add customizable logging backends and fmtlib based macros

* Change the logging backend to support multiple sinks through the
Backend Interface
* Add a new set of logging macros to use fmtlib instead.
* Qt: Compile as GUI application on windows to make the console hidden by
default. Add filter configuration and a button to open log location.
* SDL: Migrate to the new logging macros

src/common/string_util.cpp

@@ -484,5 +484,4 @@ const char* TrimSourcePath(const char* path, const char* root) {
     }
     return path;
 }
-
 } // namespace Common