Support resizing windows

[JonathanArns]

I would like similar resizing functionality to what is possible with tmux integration plugins, bound for example to <a-h> <a-j> ...

It should resize the vim window if possible in the selected direction, otherwise resize the containing kitty window.

Currently I use my own DIY nvim kitty integration, quite similar to this plugin, but if you were to get this feature going, I would rejoice and start using this plugin.

[knubie]

@JonathanArns Not a bad idea, would you mind sharing your DIY integration so that I can take a look?

[JonathanArns]

This commit basically contains it (except some vim mappings I think).
You will notice that I have taken especially one of the kittens directly from your plugin ;)
I have the same keybindings for resizing kitty and nvim windows. The only thing missing is the special case for using those from within nvim to resize the containing kitty window. For inspiration, the tmux nvim plugin that I removed from my config in the same commit does have that feature.