textproc/py-mkdocs-material: New port

Create a branded static site from a set of Markdown files to host the
documentation of your Open Source or commercial project – customizable,
searchable, mobile-friendly, 50+ languages. Set up in 5 minutes.

WWW: https://github.com/squidfunk/mkdocs-material

(cherry picked from commit 83ba44bb8308b6b6c1a731e63e52f6d3ce9ebef7)

Approved by: fluffy, riggs (ports-secteam)