ci: Add semver-compliant CI-CD and poetry dependency management

[matteo4diani]

This PR fixes issue #87.

Overview

CI-CD pipeline consisting of:

1. A Quality job that for the time being just executes unit tests.
2. A Release job that releases to GitHub and publishes to PyPI using python-semantic-release and poetry.

This pipeline automates semantic versioning and distribution of Python projects by leveraging conventional commits.

From my fork, I have done some test releases on PyPI: https://pypi.org/project/auton-survival-demo/

For a demo + docs of this CI-CD pipeline in a simplified project see https://github.com/matteo4diani/poetry-packaging-demo

Caveat

• Needs a PYPI_TOKEN repository secret holding a PyPI API Token to function https://pypi.org/help/#apitoken
• Repository's main branch should be protected and allow only squashed commits
• To correctly use this pipeline we must enforce semantic commits on master, we can use https://github.com/apps/semantic-pull-requests