Rewrite CI to powershell

[bodand]

This task is low priority.

The current CI system uses a handful of small snippets of Windows Batch and bash scripts to try to get the CI to work. However, as you know, Batch is horrible and bash is not much better.

Since the new Powershell is cross-platform and works as-is on Windows CI, we can use PowerShell scripts to automate the CI tasks without using neither Batch or bash. This will ease maintainability since PowerShell uses mostly sane syntax, and installing it shouldn't slow things down that much on non-Windows, and on Windows, where chocolatey is slow, it is preinstalled.

[bodand]

as of right now with the refactored cirrus.yml file, this does not seem that big of a problem