Add support for signing Authenticode PE Image

[xoofx]

Checksum is supported, but the signing with PKCS#7 would require some work. Should be relatively straightforward to support with https://learn.microsoft.com/en-us/dotnet/api/system.security.cryptography.pkcs.cmssigner

Also see Windows Authenticode Portable Executable Signature Format (.docx)

[spouliot]

You can also lookup the (decade old) implementation inside Mono.Security.dll which was used to implement Mono's version of signcode.