Use UICommon's game list code on Android

Deduplicates code, and gets rid of some problems the old code had
(such as: bad performance when calling native functions, only one
disc showing up for multi-disc games, Wii banners being low-res,
unnecessarily much effort being needed for adding more metadata).

Source/Android/jni/AndroidCommon/AndroidCommon.h

@@ -0,0 +1,12 @@
+// Copyright 2018 Dolphin Emulator Project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <string>
+
+#include <jni.h>
+
+std::string GetJString(JNIEnv* env, jstring jstr);
+jstring ToJString(JNIEnv* env, const std::string& str);