Reformat repo

[SamFerracin]

This PR reformats the repository. In particular:

• Adds a pyproject.toml with
  • Dependencies on samplomatic (which brings qiskit with it) and pydantic
  • "dev" dependencies on pytest, ruff, pre-commit
• Adds ruff and pre-commit.yaml
• Rewrites the git ignore
• Modifies the github workflows

[SamFerracin]

@ihincks we need to remove python3.8 from the required checks. We won't be able to run those tests since qiskit requires >=3.9

[ihincks]

@ihincks we need to remove python3.8 from the required checks. We won't be able to run those tests since qiskit requires >=3.9

This is now solved it looks like?