Oniongroove prototype - first iteration

Description

Write an early prototype/proof of concept for Oniongroove.

It does not need to implement the full spec.

In fact, here we're mostly looking after how a rewriting reverse proxy using Arti could be, and which design choices we can make that brings improvements over Onionspray.

Tasks

• Setup a development environment that builds Arti (!4 (merged)).
• Setup container configuration (!5 (merged)).
• Initial proxy implementation (!7 (merged)).
• On the fly TLS certificate generation (!8 (merged)).
• Support for the main configuration file and setup script.
• Reorganize the codebase: split and Arti and Onionspray python methods into files, split lua code from config.
• Implement basic CLI actions: start, stop, restart and status.
• Documentation update, including a diagram for the prototype.
• Make the 0.0.2 release.