Wrap the display globals in a struct (#16998)

* Wrap the display globals in a struct

Makes it easier to search/replace these, for future refactorings.

* Some renaming

* Qt buildfix, also fix the Qt build on Mac (got broken with battery changes)

* Attempt at buildfixing ios

* UWP buildfix

Common/System/Display.cpp

@@ -1,27 +1,11 @@
 #include "Common/System/Display.h"
 #include "Common/Math/math_util.h"
 
-int dp_xres;
-int dp_yres;
-
-int pixel_xres;
-int pixel_yres;
-
-float g_dpi = 1.0f;  // will be overwritten with a value that makes sense.
-float g_dpi_scale_x = 1.0f;
-float g_dpi_scale_y = 1.0f;
-float g_dpi_scale_real_x = 1.0f;
-float g_dpi_scale_real_y = 1.0f;
-float pixel_in_dps_x = 1.0f;
-float pixel_in_dps_y = 1.0f;
-float display_hz = 60.0f;
-
-DisplayRotation g_display_rotation;
-Lin::Matrix4x4 g_display_rot_matrix = Lin::Matrix4x4::identity();
+DisplayProperties g_display;
 
 template<class T>
 void RotateRectToDisplayImpl(DisplayRect<T> &rect, T curRTWidth, T curRTHeight) {
-	switch (g_display_rotation) {
+	switch (g_display.rotation) {
 	case DisplayRotation::ROTATE_180:
 		rect.x = curRTWidth - rect.w - rect.x;
 		rect.y = curRTHeight - rect.h - rect.y;