New port: net/librespeed-cli: Command line client for LibreSeed

This is the CLI part of LibreSpeed which is a very lightweight speedtest.
With the CLI it's possible to run a speedtest from the command line interface.
The server part can be found in www/librespeed.

WWW: https://github.com/librespeed/speedtest-cli

PR: 246609
Submitted by: Dries Michiels <driesm.michiels@gmail.com>