Enable some keys by default and enable more on request

if the user chooses to use such keys in the config.

src/logid/InputDevice.h

@@ -58,6 +58,7 @@ namespace logid
 
         static uint _toEventCode(uint type, const std::string& name);
 
+        bool registered_keys[KEY_CNT];
         libevdev* device;
         libevdev_uinput* ui_device{};
     };
@@ -65,4 +66,4 @@ namespace logid
     extern std::unique_ptr<InputDevice> virtual_input;
 }
 
-#endif //LOGID_INPUTDEVICE_H
+#endif //LOGID_INPUTDEVICE_H