First step for packaging the project

Packaging simplifies the process to install Concerto on nodes with pip. Before thinking about pushing Concerto into the pip repository, we could package it to enable pip install by targeting this git repository.

Currently, the following fails:

$ pip install git+https://gitlab.inria.fr/VeRDi-project/concerto 
Collecting git+https://gitlab.inria.fr/VeRDi-project/concerto
  Cloning https://gitlab.inria.fr/VeRDi-project/concerto to ./pip-req-build-8ocb_ikr
  Running command git clone -q https://gitlab.inria.fr/VeRDi-project/concerto /tmp/pip-req-build-8ocb_ikr
    ERROR: Command errored out with exit status 1:
     command: /tmp/venv/bin/python3 -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-req-build-8ocb_ikr/setup.py'"'"'; __file__='"'"'/tmp/pip-req-build-8ocb_ikr/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' egg_info --egg-base /tmp/pip-req-build-8ocb_ikr/pip-egg-info
         cwd: /tmp/pip-req-build-8ocb_ikr/
    Complete output (5 lines):
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "/tmp/venv/lib/python3.7/tokenize.py", line 447, in open
        buffer = _builtin_open(filename, 'rb')
    FileNotFoundError: [Errno 2] No such file or directory: '/tmp/pip-req-build-8ocb_ikr/setup.py'
    ----------------------------------------
ERROR: Command errored out with exit status 1: python setup.py egg_info Check the logs for full command output.