[Systems] Container org.sugarlabs.www-rebuilder added to sugarlabs-infra

[James Cameron]

Docker container org.sugarlabs.www-rebuilder on freedom has been
placed on GitHub for reference and maintenance;

https://github.com/sugarlabs-infra/www-rebuilder

This followed a question on a pull request.  I didn't know how it
worked, and couldn't find where it was source-hosted.  If anyone has a
repository with more history, please speak up.

-- 
James Cameron
http://quozl.netrek.org/