Add outer gap

[Naatan]

It would be great if we could also define a "gap" for the outside of the windows.

So basically gaps outer as per i3.

[Glanzer]

Also, I think we can afford more than 10-pixel wide gaps on contemporary screens.

[mpolidori]

@emasab Hey, just wondering if this is on your radar at all? I absolutely love this extension and this is the only feature missing (in my opinion). I looked through the code a bit, but I'm not really fluent in JS. I'd consider submitting a PR at some point if this is a feature you're interested in, and more importantly, if I can figure out how to implement it.

[emasab]

@mpolidori this feature should be added, just I have to work on Wayland compatibility before, as more and more people are trying to test it with Wayland and reporting the related issues.

[mpolidori]

@emasab Okay. Great to hear that it's a future possibility! Thanks.