security/py-dirhash: New port: Python module and CLI for hashing of file system directories

A lightweight python module and CLI for computing the hash of any directory
based on its files structure and content.

• Supports all hashing algorithms of Python's built-in hashlib module.
• Glob/wildcard (".gitignore style") path matching for expressive filtering of files to include/exclude.
• Multiprocessing for up to 6x speed-up

The hash is computed according to the Dirhash Standard, which is designed to
allow for consistent and collision resistant generation/verification of
directory hashes across implementations.