Add another horizontal (or landscape screen) keyboard setting

[Jeiii20]

Based on the Samsung Keyboard, as I've been got used to the native landscape mode keyboard, I am missing it on HeliBoard, while I just have the setting to split the keys so far, and it'd actually be a very nice idea to add this setting into the keyboard for better and faster typing.

For better explanation, I've gotten a perfect example attached below:

By implementing this setting, buttons like hide keyboard and toggle between switch keyboard/speak aloud may appear at both sides.