Use PEP518 and Poetry instead of requirements.txt

[henryx]

According to PEP518, setuptools is superseded to pyproject.toml. This change permit to switch to a more simpliest management instead of old method. Also, using in conjunction with Poetry as dependency management, it permit to define more fine grained dependencies respect to older method

[ioggstream]

0. PEP518 only mandates pyproject.toml. It does not mandate poetry. I think that Use PEP518 and Poetry instead requirements.txt and setuptools #26 should only add pyproject.toml without adding poetry. This can be added in future PRs/issues.
1. Do the new tools support the python version used in current projects (e.g. py3.7, py3.8)?

[ioggstream]

We can switch to python build module in twine to support building with pyproject.toml