add WSL support

[remoe]

add WSL support #523

The DOCKER_CERT_PATH environment will be changed with wslpath tool.

Here you find a documentation how one can use minikube on windows:

• https://medium.com/@ddebastiani/install-kubernetes-on-windows-wsl-c36f6b2571d2
• https://www.jamessturtevant.com/posts/Running-Kubernetes-Minikube-on-Windows-10-with-WSL/

After this installation one need to correct the kube config with:

USERNAME=$(id -n -u)
kubectl config set-cluster minikube --certificate-authority=/mnt/c/Users/${USERNAME}/.minikube/ca.crt
kubectl config set-credentials minikube --client-certificate=/mnt/c/Users/${USERNAME}/.minikube/client.crt --client-key=/mnt/c/Users/${USERNAME}/.minikube/client.key
kubectl config set-context minikube --cluster=minikube --user=minikube

[dlorenc]

I'm not a fan of having this at both the package level and set through a function. Could we drop this here and always return the result of detectWsl?

[remoe]

then we don't cache. Ok.

[dlorenc]

Could you move this constant to the package level?

[dlorenc]

Would it make more sense to use exec.LookPath with minikube.exe instead of this environment variable to find the path to Minikube?

[remoe]

good idea. done.

[dlorenc]

Sent #698 to fix that.