android: Expose interface for getting settings from native code

Completely removes code related to parsing the settings file on the java side. Now all settings are accessed via NativeConfig.kt and config.cpp has been modified to be closer to the core counterpart. Since the core currently uses QSettings, we can't remove reliance from Wini yet. This also includes simplifications to each settings interface to get closer to native code and prepare for per-game settings.

src/common/settings.cpp

@@ -159,6 +159,8 @@ float Volume() {
 
 const char* TranslateCategory(Category category) {
     switch (category) {
+    case Category::Android:
+        return "Android";
     case Category::Audio:
         return "Audio";
     case Category::Core: