Add support for source code in WSL

[adrianAtProresult]

Hi, I'm currently doing development with the source code residing on the Windows host, mounting or syncing it into a docker container in Kubernetes. For a more native linux development experience, I wanted to put the source code directly in WSL instead.

I quickly discovered that I could not specify a custom local installation directory in the WSL environment:

Note the message Cloud SDK Version: not installed. Clicking Click here to download the Cloud SDK simply takes me to the documentation for Cloud Code, and is not helpful as I have already installed the Cloud SDK in WSL. Using Allow the plugin to manage and install the Cloud SDK seems to default to installing the plugin in Windows, which makes it unusable in WSL context. Changing \\wsl.localhost\ into \\wsl$\ in the directory input did not have any effect either. I guess they are one and the same, as I can switch between them in the individual executables and both forms are accepted and recognized.

Paths to individual executables for Skaffold, Kubectl and Minikube seems to be recognized, but the Cloud SDK directory remains elusive. I've tried specifying pretty much every subfolder and parent folder to try and make this work, to no avail. If the Cloud Code plugin would recognize the Cloud SDK directory in WSL, I think it could be possible to exclusively develop applications in WSL without having to deal with the Windows file system at all, which would be awesome.

I hope you can consider taking a look at the possibilities available here.