Compute Authentihash

It would be nice to be able to compute a PE binary "Authentihash" according to a hash algorithm.

This basically requires hashing the whole PE binary except: Windows checksum field, Certificate Table entry in Data Directory, Certificate Attributes entries somewhere after the sections.

I suggest proceeding by finding all the regions of interest, including the "junk at the end" (which can potentially contain other things).

I will try to hack something and submit it as a PR.

No file or test is named. Start by locating the PE parsing and hashing entry points, then trace the Windows checksum field, Certificate Table entry, certificate attributes after the sections, and trailing data. Done means computing the Authentihash while excluding exactly those regions, with coverage for binaries containing each region.

Written by the indexing model from the issue text.