clearFort method
Clears everything inside the Fort except Does not clear Boxes that contain the GENERAL_KEY Boxes will remain open even after the Fort is cleared so they can still be access synchronously
Implementation
Future<void> clearFort() async {
Iterable<String> keys = openBoxes.keys.skipWhile((value) => value == GENERAL_KEY);
for(String key in keys){
await clearBox(key);
}
}