v0.1.8: 30x power saving and more

- Added FPS option with default value of 24. Reduce GPU power consumption significantly.

- Added option to hide the book for cleaner desktop. You can open the book from the system tray now.

So apparently I left the max fps at default value which is uncapped, and it's generating huge amount of unnecessary frames which is taxing on the GPU. I've added a default fps of 24 (animations are 8 or 12 fps so it should be plenty enough), but you can change it to something higher if you want.

From my testing on a 1440p monitor with a 9070 XT:

- Uncapped (running ~750fps), use around 29% of GPU.

- 60 fps, uses around 2.4% of GPU

- 24 fps, uses around 1.0% of GPU