Add WSL guide

[minikN]

I'd appreciate feedback / suggestions / constructive criticism. I'll proof read it tomorrow but there are likely to be some typos.

Also I'd be great if someone could test it as well. As of now I've only tested it for myself.

[daviwil]

Some notes from my installation experience:

• Need to link directly to the Busybox releases page, I went to the wrong place and couldn't find the rootfs.tgz file
• When I tried to create the new WSL 2 instance I received an error "The request is not supported", it turns out that I needed to turn on Virtual Machine Platform in Windows features

More notes to come as I continue!

[minikN]

Some notes from my installation experience:

• Need to link directly to the Busybox releases page, I went to the wrong place and couldn't find the rootfs.tgz file
• When I tried to create the new WSL 2 instance I received an error "The request is not supported", it turns out that I needed to turn on Virtual Machine Platform in Windows features

More notes to come as I continue!

Thanks @daviwil

I fixed the first issue in a86432e.
I'm not sure about the second issue though. There is a Prerequisites section linking to the Microsoft docs for WSL2. I believe your issue is described there. Would you like to have the WSL2 setup directly in the guide instead of linking to the official docs?