Support key binds mapping

[yanganto]

fix #15

[lusingander]

Thank you, I'm checking

[lusingander]

Thank you for responding!

• To address some of the issues with event handling, we may be able to make handle_user_event something like handle_event(UserEvent, KeyEvent) and leave it up to each View or Widget like in the original implementation rather than managing insert_mode on the App.

[lusingander]

Thanks for the correction, I added some comments.

[yanganto]

Hi @lusingander,
Thanks for the review. Now everything is good to go.

[lusingander]

Thanks so much, please check only the ci error? (I think it's a missed fix in the test code)

[lusingander]

Great!!