feat: reload font by updating config and use Rc instead of Arcs

[JarKz]

Motivation

The font doesn't reloads when the config file updates because of expensiveness. I mean that some font files are large like nerd-fonts. So I decided do it more later. Now I think the application is ready to reload fonts.

Main changes

I figured out that there is not need to use Arc<T> because it is enough to throw the Renderer initialization into child thread and initialize the InternalChannel separately. So, now in the renderer module uses Rc<RefCell<T>> which is faster than atomic analogues.

With it I've added the font reload after checking the font name. If the font names are same, font won't reload.