Make roles available in ansible galaxy

[postfalk]

Thank you for working on this. It has been very helpful. It would be even more helpful if the roles would be available in ansible-galaxy.

The problem with this repo is that it cannot be used as a dependency without customizing the code inside. E.g. LoRaWAN region settings shouldn't be hard-coded in the template. They could be set in the defaults of the retrospective role this way they code be overwritten externally.