win sign MSI to avoid UAC warning

[pauliacomi]

Some more info here

• https://docs.microsoft.com/en-us/windows/msix/desktop/desktop-to-uwp-manual-conversion
• https://docs.microsoft.com/en-us/windows/msix/package/create-app-package-with-makeappx-tool
• https://docs.microsoft.com/en-us/windows/msix/package/create-certificate-package-signing