Add Windows version

[GuillaumeBernardFGTech]

Hello, thank you for this awesome tool!

As I'm stuck on windows at work, and not allowed to install WSL, I created the necessary powershell script and compiled the tool for windows.

It really helps me and my colleagues in our day to day work, so we decided to clean it up and submit this PR to help others. I use it since 2 month on windows 10 and 11, using windows terminal with powershell 7, it works great. It's even better with Ho My Posh and the kubectl segment to display the current context in the prompt

What I changed

• Makefile: add Windows AMD64 build
• Github CI: add Windows binary to the release
• Completion.go: Add cobra autocompletion for powershell
• Init.go: add powershell script
• Documentation: add install instructions for windows

Related issues

• Fixes https://github.com/danielfoehrKn/kubeswitch/issues/64