GitLab

* Python 3.8 is now what we get in Colab, use it in our Conda as well
* Fix imports, make some unconditional - chain of depencencies makes them
  needed even for relax_prediction==False
* Mitigate spurious error "A UTF-8 locale is required. Got ANSI_X3.4-1968"
  which makes all shell commands defunct - use shutil.make_archive()