Replaced PyInstaller with WinPython for the portable Windows release.

• I spent a lot of time deleting every piece of the python standard library not required to run nsz in order to save storage and speed up extraction time by having less files to extract.
• This was done because PyInstaller triggered false positive detections on Windows Defender as reported in #82
• Tested on Windows 7, Windows 10 and Windows Server 2019

This version ONLY affects the portable Windows release. The PIP release wasn't updated as only the deployment of the Portable windows build is affected by this change.