Add kubectl config setup instructions for Windows

[jimangel]

Since Windows went GA in 1.14, it would be nice to leverage a simple OIDC kubectl context setup similar to the easy setup for linux (outputted in gangway).

Current issues are:

• stdout redirection creating the CA
• backslash escaping lines does not translate

We could have 2 info boxes (PowerShell and BASH or Windows and Mac / Linux). My preference would be to model around PowerShell vs. CMD. I'll help work on this if it doesn't get a ton of traction.

[alexbrand]

Hey @jimangel, thanks for opening this issue. This is actually a duplicate of #102, so I am going to close this one. Please do add a comment on #102 with your thoughts. Thanks again!