Refactor ActivityManager calls

src/activities/Activity.cpp

@@ -12,8 +12,6 @@ void Activity::requestUpdateAndWait() { activityManager.requestUpdateAndWait();
 
 void Activity::onGoHome() { activityManager.goHome(); }
 
-void Activity::onSelectBook(const std::string& path) { activityManager.pushReader(path); }
-
 void Activity::startActivityForResult(std::unique_ptr<Activity>&& activity, ActivityResultHandler resultHandler) {
   this->resultHandler = std::move(resultHandler);
   activityManager.pushActivity(std::move(activity));