Packaging: Add Poetry, add Pytest, add CI

[pedroCollogno]

Description

• Add Poetry for packaging and (later) testing
• Start writing UTs with Pytest
• Add a GH Actions CI

Fixes #8

Type of change

• Refactoring
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

It's literaly a test

Checklist:

• I have performed a self-review of my code
• My commits are self contained changes with descriptive messages
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• (If relevant) I have written a test for my change
• New and existing tests pass
• Any dependent changes have been merged and published in downstream modules
• (If relevant) If there's a visual change, I added a screenshot to the PR