GameFile: Support HBC-style XML metadata

This feature was originally exclusive to the previous iteration of
DolphinQt (the one that was the reason for the current iteration
being named DolphinQt2 initially).

https://bugs.dolphin-emu.org/issues/8949

Source/Core/UICommon/CMakeLists.txt

@@ -32,6 +32,7 @@ PUBLIC
   common
   cpp-optparse
   minizip
+  pugixml
 
 PRIVATE
   $<$<BOOL:APPLE>:${IOK_LIBRARY}>