[NEW] www/pydio-cells: nextgen file sharing platform

Installed on your own infrastructure, Pydio Cells provides a central
place for your users to collaborate and share files internally and
externally, while empowering your IT admins to monitor and protect your
company's data.

WWW: https://pydio.com/en/features/pydio-cells-overview
GitHub: https://github.com/pydio/cells

Reviewed by: koobs
Differential Revision: D30199