With this commit I have prepared a full basic project structure, so far
it doesn't embed phoenix itself and also no kit parts. It includes the
whole Drone pipeline to continously publish binaries on push and on tag
to our download mirrors (will be available at
https://download.owncloud.com/reva/phoenix) and also publishes
Docker images at owncloud/reva-phonix. For the Docker image auto_tag is
enabled, which means latest is always based on the master branch and
tags are automatically converted to minor, major and patch release tags.
