Xqueue was mostly broken in the previous releases. In this version, we
address the following issues:
- Proper initialisation by creating the right users
- Shift from 8040 to the more standard 8000 port
- Expose xqueue service on the internet for accessing its API
- Properly define the xqueue name ("openedx")
- Make sure that all logs go to the console
- Add convenient CLI for using the awkward Xqueue API
- Properly document how to use Xqueue
