Code sign the Windows releases

[ErikBjare]

We need to codesign Windows releases to avoid false positives by antivirus systems (see #181).

Has some CI config overlap with code signing the macOS releases, as worked on in #620

• Official docs from Microsoft: https://docs.microsoft.com/en-us/previous-versions/windows/internet-explorer/ie-developer/platform-apis/ms537361(v=vs.85)?redirectedfrom=MSDN
• PyInstaller recipe: https://github.com/pyinstaller/pyinstaller/wiki/Recipe-Win-Code-Signing

I will buy a certificate, but open to anyone doing the CI work necessary to get it working (with a sham certificate as a placeholder).

[zp6]

I have submitted a PR to address this bounty: #1304

Please review when you get a chance. Thank you!