devel/py-libevdev: add new port

python-libevdev is a Python wrapper around the libevdev C library.
It provides a Pythonic API to read events from the Linux kernel’s input device
nodes and to read and/or modify the device’s state and capabilities.

Sponsored by: Serenity Cybersecurity, LLC
Closes: https://github.com/freebsd/freebsd-ports/pull/273