Graphics: Adapt aspect ratio when SBS/TAB 3D is used

Adds support for choosing to present the full resolution
independently to each eye when using side-by-side or
top-and-bottom 3D.

Source/Core/VideoCommon/VideoConfig.h

@@ -241,6 +241,7 @@ struct VideoConfig final
 
   // Stereoscopy
   StereoMode stereo_mode{};
+  bool stereo_per_eye_resolution_full = false;
   int iStereoDepth = 0;
   int iStereoConvergence = 0;
   int iStereoConvergencePercentage = 0;