Rework the dockerfiles

[DrAnaximandre]

The current docker chain system is a bit complicated and difficult to understand given the number of layers.

We might want to rework that.

• [ ] create full docker containers for each service
  • [ ] controller
  • [ ] worker sklearn cpu
  • [ ] worker keras cpu
  • [ ] worker keras gpu
  • [ ] broker
  • [ ] mongo models
  • [ ] mongo results
• [ ] have the dockerfiles in the github repo of python-alp