Path code cleanup, move some UI code (#21037)

* Move a bunch of path logic into Core/Util/PathUtil.cpp/h

.

* Move GameImageView out from SaveDataScreen

* More cleanup, add a translation string

UI/NativeApp.cpp

@@ -111,6 +111,7 @@
 #include "Core/Util/PortManager.h"
 #include "Core/Util/AudioFormat.h"
 #include "Core/Util/RecentFiles.h"
+#include "Core/Util/PathUtil.h"
 #include "Core/WebServer.h"
 #include "Core/TiltEventProcessor.h"
 
@@ -257,16 +258,6 @@ void PostLoadConfig() {
 #endif
 }
 
-static Path GetFailedBackendsDir() {
-	Path failedBackendsDir;
-	if (System_GetPropertyBool(SYSPROP_SUPPORTS_PERMISSIONS)) {
-		failedBackendsDir = GetSysDirectory(DIRECTORY_APP_CACHE);
-	} else {
-		failedBackendsDir = GetSysDirectory(DIRECTORY_SYSTEM);
-	}
-	return failedBackendsDir;
-}
-
 static void CheckFailedGPUBackends() {
 #ifdef _DEBUG
 	// If you're in debug mode, you probably don't want a fallback. If you're in release mode, use IGNORE below.