WIP: Conda ci

Ok I have configured some working CI here which uses small conda environments, caches things, and uses conda packages for our test process and upload process.

I have a couple of issues still:

• upload of packages
  • Don't know how to upload the files like you did with wheels.
  • After a file is uploaded you need to run conda index to reflect the new changes.
• the port process is somewhat explained here: https://gitlab.idiap.ch/bob/bob/wikis/ci-setup-with-conda but needs improvement.

ping @andre.anjos @tiago.pereira @mguenther @pkorshunov