Distributed Tuleap development environment grown mad and it's a challenge to understand how things piece together.

The purpose of this contribution is:

• Remove dependency on enalean/tuleap-dev docker image.
  • This image was needed at the project start because it was CentOS7 while the rest of Tuleap was CentOS6. It's no longer the case so we should align everything on the default development image
• Remove dead code. With progress of standard configuration tooling, a lot of code in tools/Configuration is no longer needed, let's purge it
• Finally the docker-compose-distlp.yml that should allow to start a distlp dev stack is never used and un-likely to work if we attempt to start it. In the mean time, distlp tests are run everynight. The tests are enough to guaranty that we don't break anything and are the only reliable base if we ever need to start a dev stack at some future point.